UK Cotton growers facing complete crop loss after alleged herbicide drift

On Christmas Day farmers around Walgett in north-west New South Wales noticed their toddler cotton plants had begun to wither. Leaves began to curve and die, killing some vegetation and stressing others.Within days, it was clear Walgett was once dealing with a major incident that had affected nearly 6,000 hectares (60 squarekm) of cotton farms attaining as far as Burren Junction, and Rowena.

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The perpetrator is assumed to be a giant plume of 2-4,D, a herbicide that is used to kill broadleaf weeds in fallow fields and in some cereal vegetation. a Couple Of days previous it had rained, which prompts the weeds to sprout and farmers started spraying – regardless that who is responsible for the 2-four,D plume remains a mystery.

    The spray, possibly used at night time, is thought to have been trapped in an inversion layer in the environment and then drifted over the highly sensitive cotton vegetation.

    But cotton may just be the agricultural an identical of the canary within the coalmine. Jo Immig, coordinator at the National Toxics Network stated the results of herbicide flow were given public attention when cotton used to be affected and there have been financial losses, however off-target spraying used to be most certainly affecting different areas, such as bushland, national parks, waterways and population centres, with out attracting the similar type of scrutiny.

    “It’s not as obvious when it’s in other parts of the environment. The regulators haven’t had nearly enough concern about pesticide drift and its impacts,” she mentioned.

    “From our pespective, this is evidence that spray drift happens regularly and it explains how pesticides get into the the food chain and the waterway.”


    5,000 hectares of cotton thought to be affected by off-target spray drift


    Bernie Bierhoff of Walgett Cotton Growers’ Association

    So severe is the cotton crop damage that the city convened an urgent assembly of all farmers and agronomists on 4 January to establish its extent and map out a plan to prevent a repeat.

    Severe cotton leaf injury from near Walgett in northern New South Wales. Photograph: Cotton Australia
    The vice chair of the Walgett Cotton Growers’ Association, Bernie Bierhoff, says cotton plants on greater than 10 farms, together with his personal, have been affected by the off-target spray glide – some critically.

    “Spray drift damage is a terrible blow for the affected cotton growers, who are already struggling with limited access to water for irrigation this season,” Bierhoff said.

    “While it is still early days, the information we have to date suggests more than 5,000 hectares of cotton has been affected by off-target spray drift in the days leading up to December 25.”

    Some cotton growers are going through entire crop loss. Others are weighing whether or not to remove broken vegetation to conserve water.

    The herbicide was additionally breathed in by way of farmers and their households and entered the waterways.

    2-4,D is without doubt one of the oldest herbicides used in Australia and reasons broadleaf weeds to grow uncontrollably and die, with out hurting grass plants comparable to wheat.

    But regardless of its long historical past of use because the 1940s, it stays underneath scrutiny. The World Health Organisation’s International Agency for Research on Cancer affirmed its classification at 2B in 2015, as “a chemical that possibly causes cancer”.

    2-four,D was once probably the most substances in the defoliant, Agent Orange, although no longer its most toxic element.

    Often herbicide directions specify that they are not to be used above a definite temperature, say 30C, because higher temperatures make them become more unstable and evaporate into the ambience.

    “Unless they were spraying at night or very early in the morning, it’s hard to believe this incident at Walgett involved spraying within the guidelines,” Immig stated.

    She stated some newer products had a lot more stringent tips on when and how they could be used, including necessities for buffer zones, nozzle dimension, windspeed, temperature and bans on use when there are temperature inversions.

    But older products equivalent to 2-four,D don’t seem to be matter to the same necessities. The Australian Pesticides and Veterinary Medicines Authority (AVPMA) says it’s carrying out a review of its policy on spray waft, however there is no indication of when it might document.

    This is not the first time off-target float has decimated cotton vegetation, however the problem is also getting worse as local weather trade drives up temperatures.

    In January 2016 a identical phenomenon burnt up 60,000 hectares of cotton close to Walgett, leading to 20% of the crop demise and losses estimated at $20m.

    In February 2017 30,000 hectares of cotton was once damaged round Griffith in NSW.

    Bierhoff says farmers in the Walgett house have now agreed to chorus from evening spraying of 2-4,D – when inversion layer effects are more likely to occur – and to voluntarily chorus from using the herbicide between October and February. Other costlier choices shall be utilized in that length.

    None of the regulators were up to examine, he says.

    APVMA also says it has 2,four,D under evaluation and will document via April, though the review has been operating for nearly 15 years. The highly unstable ester version of 2-4,D was banned in 2006 in Australia, 20 years after it used to be withdrawn in Europe.

    In the intervening time, APVMA is going via an unprecedented upheaval on account of the federal government’s determination to move it to Armidale in National party leader Barnaby Joyce’s electorate.

    Senate estimates committees had been instructed the company has struggled to persuade group of workers to move to Armidale, with the outcome that almost part the company’s scientists had left and 20% of jobs were vacant on the end of 2017.

    A report by consultants Pegasus Economics really helpful the company recruit body of workers from overseas and imagine e-working arrangements as a way to stay running.

    Cotton: Pest, Symptoms of damage, Seasonal occurrence, Natural enemies & Pesticides recommended

    Plant protection strategy and activities have significant importance in the overall crop production programmes for sustainable agriculture. Variation of Bt gene expression in different cultivars over time and efficacy to bollworms are the main concern now a days, studies undertaken on Earias spp proved the concerned. Similarly the efficacy of Bt cotton in the field is losing efficacy against the pink bollworm, survey conducted revealed high infestations in green bolls. Monitoring of lepidopterous pest population viz sex pheromone and light traps was carried out and forecast the increasing trend in all bollworms population.

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    Studies on red and dusky cotton bugs continued and efforts are made to find bio agents for long term solutions. Seed treatment effect and development of natural on early and normal planting studies revealed that the population of jassid was more on early sown field than normal sowing also the natural fauna was recorded higher in the early sown. The distinct efforts of researchers of the section have proved meaningful in devising pest management strategies against common and new emerging insect pests through application of IPM. Studies are continued on host plant tolerance of CCRI, Multan and National Coordinated Bt. & non-Bt. Strains. The section also studied effect of different IPM strategies on insect pest for transgenic cotton. Screening of new insecticides was also conducted against major insect pests of cotton.

    Important pests of cotton:

    Name of pest Scientific Name Family Order
    Thrips Thrips tabaci Thripidae Thysanoptera
    Jassid Amrascadevastans Jassidae Hemiptera
    Whitefly Bemisia tabaci Aleyrodidae Homoptera
    Mealybug Phenacoccus solenopsis Psuedococcidae Hemiptera
    Red Cotton Bug Dysdercus cingulatus Pyrrhocoridae Hemiptera
    Dusky Cotton Bug Oxycarenus hyalipennis Lygaeidae Hemiptera
    Mites Tetranychustelarius Tetranychidae Acarina
    Pink bollworm Pectinophoragossypiella Gelechiidae Lepidoptera
    Spotted Bollworm Eariasvittella Noctuidae Lepidoptera
    spiny bollworm Eariasinsulana Noctuidae Lepidoptera
    American Bollworm Helicoverpa armigera Noctuidae Lepidoptera
    Armyworm Spodopteralitura Noctuidae Lepidoptera

    Symptoms of damage:

    Name of pest Symptoms of damage
    Thrips Leaves of seedlings become wrinkled and distorted with white shiny patches, older crop presents rusty appearance from a distance.
    Jassid Affected leaves curl downwards, turn yellowish, then to brownish before drying and shedding, “hopper burn” stunts young plants.
    Whitefly Upward curling of leaves, reduced plant vigour, lint contamination with honey dew and associated fungi, transmission of leaf curl virus disease.
    Mealybug The extraction of sap by the mealybug results in the leaves of the plant turning yellow and becoming crinkled or malformed, which leads to loss of plant vigour, foliage and fruit-drop, and potential death of the plant.
    Red Cotton Bug Feed on developing and mature seeds, stain the lint to typical yellow colour, reddish nymphs seen in aggregations around developing and open bolls.
    Dusky Cotton Bug Associated with ripe seeds, all stages characterized by a powerful smell, discolour the lint if crushed.
    Mites The first sign of damage is bronzing of the upper leaf surface near the petiole or leaf fold. As numbers increase, the leaves turn red and become covered in fine webbing, and affected leaves may dry and fall off.
    Pink bollworm “Rosetted” bloom pink larvae inside developing bolls with interloculi movement .
    Spotted Bollworm Bore mark in main shoot, dried and withered away shoot, twining of main stem due to auxillary monopodia, feeding holes in flower buds and bolls blocked by excrement.
    spiny bollworm Bore mark in main shoot, dried and withered away shoot, twining of main stem due to auxillary monopodia, feeding holes in flower buds and bolls blocked by excrement.
    American Bollworm Small amount of webbing on small squares injured by young larvae, squares have around hole near the base,larval frass and flaring of bracts on larger squares, clean feeding of internal contents of bolls, excessive shedding of buds and bolls.
    Armyworm Young larvae in groups skeletinise leaves and older larvae voraciously defoliate leaves .

    Seasonal occurrence of cotton pest in Pakistan:

    Name of pest Month of attack
    Thrips June and July
    Jassid July
    Whitefly July-September
    Mealybug October-November
    Red Cotton Bug October-November
    Dusky Cotton Bug Though our crop
    Pink bollworm August-November
    Spotted Bollworm July-September
    American Bollworm August-October
    Armyworm

    List of natural enemies of cotton pest:

    Predator/Parasitoid Host Attack Stage
    Green lace wings, pirate bugs Lady bird
    beetle: Coccinella
    septempunctataMenochilus
    sexmaculatus, Brumodies sp. , Scymnus
    Thrips Nymph and adult
    Green lace wings Jassid All stages
    Lady bird beetle: Coccinella
    septempunctataMenochilus 
    sexmaculatus, Brumodies sp. , Scymnus 
    Eretnocerus serius
    Whitefly Egg and Numph
    Lady bird beetle: Coccinella
    septempunctataMenochilus 
    sexmaculatus, Brumodies sp. , Scymnus , 
    aenasius bamby wali.
    Mealybug Adult and larvae, adult
    Lady bird beetle: Coccinella
    septempunctataMenochilus 
    sexmaculatus, Brumodies sp. , Scymnus

    Shield bug Eucantheconidea furcellata 
    Apanteles angaleti 
    Elasmus johnstoni
    Pink bollworm Larvae
    Lady bird beetle: Coccinella 
    septempunctataMenochilus 
    sexmaculatus, Brumodies sp. , Scymnus
     
    Shield bug Eucantheconidea furcellata 
    Mirid bug Nesidiocoris tenius
    Spider: Oxyopes sp., Clubionia sp., Thomisus sp.
    Brachymeria nephantidis
    Spotted Bollworm Larvae
    Lady bird beetle: Coccinella
    septempunctataMenochilus 
    sexmaculatus, Brumodies sp. , Scymnus

    Shield bug Eucantheconidea furcellata 
    Spider: Oxyopes sp., Clubionia sp.,
    Thomisus sp.
    Trichogramma chilonis
    American Bollworm Larvae
    Aphidius colemani, Lady bird beetle:
    Coccinella septempunctataMenochilus
    sexmaculatus, Brumodies sp. , Scymnus
    Syrphid fly
    Aphid Egg, nymph and adults
    Anthocorid bug Orius minutus 
    Wasp Eumenes petiolata and Delta sp
    Mirid bug Nesidiocoris tenius 
    Spider: Oxyopes sp., Clubionia sp.,
    Thomisus sp.
    Armyworm Larvae

    Pesticides recommended for cotton pests control under different situations:

    Sr.# Pest situation recommended insecticide Dose / acre (ml/gm)
    1 Seed treatment to control sucking insect pests at an early stage. Imidacloprid 70 WS 
    Thiamethoxam 70 WS*
    10 gm/kg seed 
    5 gm/kg seed
    2 Thrips reached ETL, during early stage of crop and clear damage symptoms are visible. Chlorfenpyr 360SC
    Spinetoram 120SC
    Spinosad 240 SC
    Imidacloprid 200SL
    Acetamiprid 20 SP
    Formathion 25 EC
    Etofenprox 30 EC 
    Or Any other suitable registered insecticide
    100
    50
    50
    80
    50
    500
    200
    3 Whitefly population reached ETL, during early stage of crop. Diafenthiuron 500 SC
    Spirotetramate 240 SC
    Acetamiprid 20SP
    Imidacloprid 200 SL
    Buprofezin 20SC
    Pyriproxyfen 10.8EC
    Any other suitable registered insecticide
    200
    125
    150
    250
    600
    400
    4 Jassid population reached ETL, during early stage of crop. Dinotefuran 20SC
    Dimethoate 40EC
    Imidacloprid 200 SL
    Nitenpyram 10 SL
    Etofenprox 30 EC
    Thiamethoxam 25 WG Or
    Any other suitable registered insecticide
    100
    350
    200
    200
    200
    24
    5 Whitefly & Jassid collectively reached ETL during early stage of crop. Dinotefuran 20SC
    Dimethoate 40EC
    Imidacloprid 200 SL
    Nitenpyram 10 SL
    Etofenprox 30 EC
    Thiamethoxam 25 WG
    Mix with IGR
    Buprfoezin 20SC
    Pyriproxyfen 10.8EC
    100
    350
    200
    200
    200
    24

    600
    400
    6 Pink bollworm reached ETL. Spinosad 240 SC
    Spinetoram 120 SC
    Spinetoram 250 WG
    Gamma Cyhalothrin
    Triazophos 40 EC
    Bifenthrin 10 EC
    Cypermethrin 10 EC
    Deltamethrin2.5 EC
    Tralomethrin
    Fenvalerate 20 EC 
    Or
    Any other suitable registered insecticide
    50
    100
    40
    100
    1000
    275
    333 / 365
    300
    80
    250 / 265

    7 Spotted bollworm reached ETL Spinosad 240 SC
    Spinetoram 120 SC
    Cypermethrin 10 EC
    Deltamethrin 2.5 EC
    Beta-Cyfluthrin 25 EC
    Cyhalothrin 2.5 EC
    Fenvalerate 20 EC
    Alpha cypermethrin 5 EC
    Or
    Any other suitable registered insecticide
    40
    40
    300 / 325
    333 / 365
    250 / 275
    333 / 370
    400 / 450
    440 / 490


    8 American bollworm reached ETL at early stage. Spinosad 240 SC
    Spinetoram 250 WG
    Chlorfenapyr 360 SC
    Emamectin Benzoate 1.9 EC
    Chlorpyrifos 40 EC
    Profenofos 500 EC
    Indoxacarb 150 SC
    Thiodicarb 80 DF
    Or
    Any other suitable registered insecticide
    100
    60
    333
    200
    1000
    1000
    175
    480

    9 Aphids reached ETL in later part of the crop life. Carbosulfan20 EC
    Diafenthiuron 500 SC
    Chlorpyrifos 40 EC
    Quinalphos 25 EC 
    Or
    Any other suitable registered insecticide
    500
    200
    750
    1250

    10 Mites reached ETL. Spiromesifen 240 SC
    Fenpyroxymate 5 SC
    Azocyclotin 25 WP
    Pyridaben 15 EC
    Amitraz 20 EC
    Diafenthiuron 500 SC
    Ethion 46 EC
    Triazophos 40 EC
    Chlorfenapyr360 EC
    Hexythiazox 10 WP 
    Or
    Any other suitable registered insecticide
    100
    200
    150
    500
    1000
    200
    1000
    600
    333
    220

    11 Armyworm attack on cotton.** Methoxyfenozide 240 SC
    Lufenuron 50 EC*
    Flubendamide 480 SC
    Emamectin Benzoate 1.9 EC
    Tebufenazide 20
    Acephate 75 SP
    Indoxacarb 150 SC
    Methomyl 42 SP***
    Or
    Any other suitable registered insecticide
    200
    200
    50
    250
    350
    750
    175
    500

    12 Black headed cricket. Bait
    Ingredients:
    1. Rice husk (Bhossi) 10 kg/acre
    2. Methamidophos½ litre
    3. Gur (Molasses) 1 kg
    4. Water As per requirement
    The formulated material is for one acre.
    13 Mealy bug infestation during early stage of crop. Acetamiprid 20 SP
    Imidacloprid 200SL
    150
    250
    14 Mealy bug infestation during late stage of crop. Profenofos 50 EC
    Methidathion 40 EC
    Chlorpyrifos 40 EC
    800
    400
    1000
    15 Dusky cotton bug. Fipronil
    Clothianidin
    Triazophos
    Imidacloprid + Fipronil
    480
    150
    660
    60
    16 Red cotton bug. Fipronil 5 SC
    Triazophos 40 EC
    Cypermethrin + Chlorpyrifos
    Triazophos + Deltamethrin
    Imidacloprid + Fipronil
    480
    660
    500
    600
    60

    Notes:Doses of the chemicals are based on the concentration given in the above table. If different formulation than given is used, dose may be adjusted accordingly.

    Cotton seed yield and its quality as affected by mineral nutrients and plant growth retardants

     Seed quality is one of the most important factors for stand establishment in cotton (Gossypium sp.), and the use of good quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailing during seed formation can affect the quality of seed produced, and hence crop establishment in the next growing season. These conditions can affect the germination of the seeds and the ability of the seedlings to emerge from soil, these being the most critical stages during the life cycle of cotton plant.

    [embeddoc url=”http://agrinfobank.com.pk/wp-content/uploads/2018/08/Cottonseed-yield-and-its-quality-as-affected-by-mineral-nutrients-and-plant-growth-retardants.pdf” download=”all”]

    Sudden death of cotton plant results monetary losses

    Cotton is one of the most important fiber and cash crop of the world. Pakistan is the 3rd largest exporter of raw cotton and a leading exporter of yarn in the world; contributes nearly 10 percent in the agriculture GDP and is a source of 60 percent foreign exchange earnings. The value addition through cotton is 8.2 percent in agriculture and 2 percent in the GDP. Sindh and Punjab are the ancient homes of cultivated cotton. It is considered white gold of Pakistan.

    The area under cultivation and production is about 3192 thousand hectares and 14265 thousand bales, respectively with 760 kg/hectare yield. The crop has maximum area in Punjab followed by Sindh and very negligible in NWFP. The yield per hectare of seed cotton in Punjab is more to that of Sindh province.

    Cotton crop is totally useful for human beings and animals from seed to waste, basically is a natural fiber that finds use in many products, range from clothing to home furnishing and producing medical products; as a result, it is always in demand though its use is subject to the strengths and weaknesses of the overall economy.

    Cotton feeds 1035 ginners and about 5000 oil expelling units, which produce 4.00 million tons edible oils. In such a way, cotton brings cash return to farmers, supply raw material to textile industry and provides employment to thousands workers, both in rural and urban areas. About two third of the harvested crop is composed of the seed which is crushed to separate its three products oil, meal and hull. Cotton seed oil is a common component of many food items, used primarily as cooking oil. The oil is used extensively in the preparation of snacks food and crackers, cookies and chips. The meal and hull are used as feed for live stock, poultry and fish. Cotton waste, meal and hull also used as fertilizer for improving soil fertility. Cotton waste is also multiuse product used for mulching in crops, substrate for artificial cultivation of edible and medicinal mushrooms.

    However, the productivity rate of cotton for Pakistan did not depart significantly from the world average (1,576 kg/ha) over the period, because of many reasons, including diseases, caused by fungi, bacteria, nematodes, viruses and physiological disorders. Lyda and Watkins (2001, www.apsnet.org) listed 3 bacterial, 17 fungal, 4 plant parasitic nematodes, 10 viral and 2 phytoplasmal and spiroplasmal diseases in world. The work carried out so far in Pakistan shows that seedling rot or wilt, root rot, boll rot, anthracnose, different types of leaf spot diseases, premature opening of bolls (Tirak), stunting and reduction in size of leaves, some nematode species, bacterial blight (angular leaf spot and boll rot), leaf curl and stenosis of cotton, found causing damage to the crop. These diseases are injurious in some areas, in some years and on some plant parts. The magnitude of disease damage depends up on the environment and cultivar. In spite of all, cotton wilt disease is the most dangerous, causes sudden death of plants and results monetary losses after infection; therefore in severely affected areas it may cause whole fields to be ploughed out.

    Several species of Fusarium and Verticillium fungi causes wilt. Both the fungi differ from one another, but cause very similar symptoms. The only reliable method for separating and identifying these diseases is taxonomy of causal fungi, both can be readily isolated and cultured from the diseased plant portions. Both the fungal wilts thrive with high nitrogen fertilizer, excessive soil moisture, thin stands and deep cultivation. Both the fungi survive for long periods (for at least a decade) in soil on organic matter and even on non-host plants. However, some of the differential general characteristics between both the wilt fungi may also help in identification and control.

    Fusarium wilt develops well in acid soils, is more prevalent in sandy soil, causes more injury when the nematodes injure the roots, can be transmitted internally in seed and prefers hotter soil than Verticillium. Whereas, Verticillium wilt thrives in alkaline soil; is more prevalent in heavy soils, does not require injury for infection, can not be transmitted internally in seed and prefers cooler soil than Fusarium.
    The wilts start appearance at seedling in case of early attack and/or may also occur at any plant growth stage. Areas of reduced or patchy plant stand can be seen in affected fields, usually spreading in the direction of irrigation flows. Symptoms include seed and seedling rot, wilting, death of seedling and adult plants, accompanied by vascular browning.

    Initially, vein clearing and leaves show a distinct loss of turgor and yellowing occurs starting at the leaf margin between the main veins, sometimes referred as leaf epinasty, followed by stunting. The stunted plants may fruit early.The yellowing progresses inward and is followed by necrosis hence defoliation occurs starting at the bottom of the plant, and consecutively towards the top, results progressive wilting of leaves and stem, defoliation and finally death of the plant (partially or wholly), some attempted regrowth. The diseased plants are pulled out easily, due to the loss of rigidity. Brown, red or yellow rings of discolored tissue observed in case of cutting the stem in crossways, mostly close to the base and plant death occur in severe cases. Fusarium wilt is a solid dark brown ring compacted with healthy white stems around the outer portion of the stem and that the infected areas observed irregular in shape and size. Water-conducting stem tissues turn brown and become inactive, resulting in wilted foliage. Leaves turn yellow between veins and eventually shed as plants die to leave bare stems. Once the fungus has colonized the plant the diagnosis is confirmed by splitting the stem to reveal dark brown, vascular discoloration and streaking characteristic of wilt, most likely causes the death of the host. The wilt diseases mostly spread in patches, but entire field may also be affected in severe conditions. Certain strains of the causal fungus only cause symptoms when plants are also infected with the root knot nematode. In those cases, galls are usually prevalent on lateral roots. Some formae speciales are not primarily vascular pathogens but Fusarium spp. may also cause foot and root rot or bulb rot in cotton.

    Cotton wilt causing both pathogenic fungi (Fusarium and Verticillium spp.) are seed-borne, may carry over for long-distance, spread from year to year by sowing infected seed; also move from field to field, farm to farm and region to region, whenever very small quantities of infested soil is transported through boots, farm equipments, vehicles, in water (irrigation and overland flows), in flood irrigation and also in infected plant material, including seed etc. The fungi sustains on the outer surface of roots of many crops and weeds and survives indefinitely in soil for at least a decade, even in the absence of cotton plants. The diseased plant debris lying in the field or in the storage space also helps both the fungi to remain alive. The cotton husks, used as cattle feed are also identified as a potential source for spread of wilt. The scientists also reported very broad host range of both the wilt causing fungi, at the species level. More than 120 different formae speciales have been identified based on specificity to host species belonging to a wide range of plant families.

    Prevention is better than cure, because control of wilt diseases is very difficult, chemical control is very costly and even is impossible to recover heavily infected, shriveled and damaged plants. However, cultivation of resistant variety is only the most easy, economical and safe method. Growers are advised to plant improved immune or resistant varieties, because these are equal to the susceptible varieties in yield, adaptation and other cultural characteristics and field practices; since new races of the fungi may develop and attack on these.

    cotton04

    However, it is necessary that growers must keep in touch with the latest information on resistant varieties and control measures. The following preventive measures also help to minimize risk of damage.• Crop rotation with non host crop is preferably recommended, because lower disease intensity has been reported in case to avoid cultivation of susceptible varieties/cultivars in the diseased area at least for three years.
    • Clean cultivation by removing infested plant materials after harvesting through deep and repeatedly tillage operations help to destroy infected plant parts from field.
    • Good drainage improves soil conditions which help to minimize the disease incidence.
    • Use of disease free and certified seed or seed treatment with suitable seed dressing fungicides before sowing is also recommended.
    • In some cases, late and deep sowing reduces disease incidence.
    • Mixed cropping with non host crops also help to check the disease.
    • 5-6 weeks mulching with colorless plastic is recommended for soil solarization and straw mulch help to maintain temperature for reducing the fungal population in crop field.
    • Uprooting and burning of diseased plants and weeds help to minimize further spread of the problem.
    • Proper irrigation and balanced fertilizer application help to grow healthy plants with the aim of more resistance against wilt and other diseases.
    • Avoid storage of plant waste material and even storage in the field, otherwise sweeping the waste material from storage space and burning or burying all plant debris must be ensured.

    Courtesy: M. Mithal Jiskani and Gul Bhar Poussio
    Department of Plant Pathology, Sindh Agriculture University Tandojam

    Cotton pests, predators and parasitoids

    Introduction

    Insect pests are one of the major limiting factors in cotton production. Of 1326 insect pests recorded on cotton worldwide, nearly 130 species occur in India. About a dozen of these arthropods are commonly present in sufficient numbers requiring their management for realizing better cotton yields.

    Sucking Pests

    Sucking pests are deleterious during early season of the cotton plant growth and developmet. Jassids, aphids, whiteflies and thrips continue in the absence of cotton with continuous production of vegetables. Besides, they survive on a variety of wild hosts during dry season. Even with the small number of immigrants, populations can build up to serious proportions as a result of rapid and prolific breeding in the cotton plant.

     

    Jassids (Amrasca biguttula biguttula Ishida)

    Jassids also referred, as leafhoppers are important sucking pests. Both nymphs and adults suck the plant sap and apparently introduce salivary toxins that impair photosynthesis in proportion to the amount of feeding.  The  affected  leaves  curl  downwards,  turn  yellowish,  then  to  brownish  before  drying  and shedding. Severe “hopper burn” stunts young plants and reduce yields.

     

    Adults are elongate and wedge shaped with pale green body; very active with sideways walk but quick to hop and fly when disturbed. Eggs are curved and deeply embedded in the midribs of large veins on the undersurface of the leaves. Nymphs are flattened , pale yellowish green with sideway movements and remain confined to the lower surface of  leaves during day time. Eleven generations have been estimated in a year. Yield loss from jassids can be reduced by growing hairy varieties.

     

    Aphids (Aphis gossypii,Glover)

    Aphis gossypii, commonly referred as cotton aphid is present in all cotton growing areas causing serious problems at times. Aphids are phloem feeders, causing direct leaf crumpling and downward curling with severe attack. Indirectly decreases cotton fibre quality as a result of sticky cotton due to deposits of honeydew on open bolls.

     

    Aphis gossypii is extremely variable in colour (dirty green, dark green, blackish brown, orange/ dirty yellow), and size with apterate (0.9 – 1.8 mm) and alate (1.1 – 1.8 mm) occuring simultaneously. They have  a  large  range  of  host  plants  with  varying  duration  of  development  and  reproductive  rate. Aggregating populations are seen at the terminal buds and largest populations are found below the leaves of the lower third of plants , where they are partially protected from high temperature. Outbreaks are common on seedlings and young plants during spells of dry weather.

     

    Heavy rainfall reduces populations by directly washing them off the plant. Host plant traits reported to have impact upon aphid resistance are plant colour, pubescence, gossypol content, chemical makeup of the plant and stem tip stiffness.  Role of coccinellids, and to some extent syrphids and chrysopids, in aphid population regulation is recognized. All are density dependent predators however frequently too late in appearance and hence chemical control is often required to reduce the population to acceptable levels.

     

    Whiteflies (Bemisia tabaci : Gennadius)

    Whitefly has been recorded on cotton in India as early as 1905 and was considered to be an insignificant pest. It  assumed major importance on  cotton  after  severe  outbreaks during  1984-85 and  1985-86 seasons in the states of Andhra Pradesh, Karnataka and Tamil Nadu and as a vector in transmission of leaf curl virus in states of Rajasthan, Haryana and Punjab.

    1. B. tabaci is a major pest in mid and late periods of cotton growing seas Damage results from direct feeding that reduces the yield. Indirect damage results from lint contamination with honey dew and associated fungi and through transmission of leaf curl virus disease.

    Adults are white and small, females are 1.1 -1.2 mm long; the males are slightly smaller. Antennae of

    females are longer than males. Genitalia of female consists outer and inner vulvulae and rounded, whereas paramors of males are extended , narrow and pointed. Parthenogenetic reproduction is also seen.

     

    Drought coupled with high temperature during crop growth, cultivation of cotton year after year with no crop rotation, excessive use of nitrogenous fertilizers and synthetic pyrethroids lead to outbreak of B. tabaci.

     

    Thrips (Thrips tabaci Lindeman)

    1. T. tabaci damages young cotton seedlings, flowers and stems. The incidence is severe in the beginning of the season during the periods of low relative humidity. With thrips attack leaves of seedlings become wrinkled and distorted, and the vegetative phase is delayed leading to late harvest.

     

    Thrips are slender and the colour of macropterous adults varies from pale yellow to dark brown. Antennae have seven segments with the first segment always paler than second segment which is usually dark. Anterior edge of the abdominal tergites is marked by a brown band. There is a single pair of pores on tergite IX. Pupation is in the soil. Thrips are usually active round the year moving from one host to another. Heavy rainfall limits the thrips population. Systemic insecticides as seed treatment or sprays offer protection to thrips at earlier stages of crop growth.

     

    Bollworms

    Major yield loss to the Indian cotton (even up to 60%) is due to bollworm complex consisting of three genera of bollworms viz. Earias, Helicoverpa and Pectinophora. The former has two species and the latter two genera with a single species each. While alternate host plants of Earias and Pectinophora are chiefly Malvales, Helicoverpa is polyphagous and has become the most important bollworm of cotton because of the increased severity of attack in almost all cotton growing areas of the country.

     

    Spotted bollworm (Earias sp.)

    Two species of Earias viz. E. insulana (Boisd) and E. vitella F. (earlier known as E. fabia), collectively known as spotted bollworms, are important pests. It has been found that E. insulana breeds on a variety of  hosts  of  different  genera  whereas  the  occurrence of      E.  vittella  is  limited  to  Gossypium and Abelmoschus. Neonate larvae cause damage to the terminal bud of the vegetative shoots and channel

    downwards or into internode during early stages of crop growth. The whole apex of main stem collapses, if the main stem growing point is affected. If the apical bud alone is damaged, there is twinning of the main stem due to the growth of axillary monopodial buds. When flower buds/bolls are attacked, the tunnel

    opening is blocked by excrement. Tunnel in bolls is often from below, angled to the peduncle. Larvae do not confine their feeding to a complete single boll and hence damage is disproportionate to their numbers. Adult moths differ with species. In E. insulana, the head , the thorax, and forewing colour varies from silver green to straw yellow, the distal fringe of wing is of the same colour. There are three distinct transverse lines of darker shade and traces of the fourth at times. Green forms are common during summer, while yellow/brown forms occur toward the end of season.

     

    Eggs are spherical, with less than 0.5 mm diameter and have light blue green colour with longitudinal ridges resembling the fruit of a poppy. Eggs are laid singly on most parts of the cotton plant (flower buds, bolls, peduncles and bracteoles) , the favored one being young shoots.

     

    Full grown larva is about 1.3-1.8 cm long, stout and spindle shaped bearing a number of long setae on each segment. Last two thoracic and all abdominal segments bear two pairs of fleshy tubercles, one of which is dorsal and the other lateral. Larva is light brown, tinged with grey to green, paler along the mid dorsal line with dark spots at the base of the setae, more pronounced on the second and fifth abdominal segments. Yellowish spots are seen at the base of tubercles of thoracic segments. Larvae of  E. insulana is generally lighter in colour, the pattern being grey and yellow than brown and deep orange. In E. vittella larval tubercles are much less prominent especially in the abdomen.

    Pupa is enclosed in cocoon shape like an inverted boat and made of tough silk of dirty white or light brown colour, usually attached to plant or plant debris on the ground.

    1. E. insulana is the most abundant species in the Punjab and E. vittella is predominant in peninsular Indi

    Abelmoschus indicum for E. insulana in the north and Abelmoschus esculentus for E. vittella in the south

    of India provide means of carry-over from one cotton season to the next.

    The braconid, Rogas aligarhensis (Qardi), offers better biocontrol of Earias spp. Parasitism rates of

    greater than 25% in eggs and 37% in pupae were recorded in Punjab (Shekhon and Verma,1988).

     

    American Bollworm (Helicoverpa armigera Hubner)

    Helicoverpa armigera has become the most important insect pest of cotton in almost every cotton growing

    area because of the wide range of cultivated and wild hosts. Larvae bore into flower buds, bolls and feed upon the internal contents. Squares injured by H. armigera usually have a round hole near the base. A small amount of webbing is often present, especially on small squares injured by young larvae. Larval frass and the flaring  of bracts on larger squares are apparent by the time larvae reach second instar. A single larva can damage 5-7 bolls. Under conditions of high humidity within plant canopy, boll rot by microbes set in and can result in extensive crop loss. Eggs are spherical with a flattened base laid on the tender foliage and calyx of squares of the cotton plant. Surface is sculptured with longitudinal ribs. Colour is white to creamy white after oviposition. As the embryo develops reddish brown band is seen centrally which gradually darkens and together with rest of egg becomes brown before hatching.

     

    Newly hatched larvae are translucent yellowish white with brown to black head capsules. The thoracic and anal shields, spiracles, thoracic legs, setae and their tubercle bases are also brown to black, giving the larvae a spotted appearance. Second instar is essentially similar but with darkened ground colour and lightened sclerotized head capsule, thoracic and anal shields and thoracic legs. The third instar has a predominantly brown ground colour. The characteristic patterning   becomes more prominent and colouring generally darker in later instars, although host diet plays a role to an extent.

    There are usually five larval instars.     Pupa is smooth surfaced, brown, rounded both anteriorly and posteriorly with two tapering parallel spines at posterior tip. Females are on an average heavier than males. Pupae are formed at a depth of 2.5 – 12.5 cm   in the soil. Pupal period ranges from 6 days at 35

    °C to over 30 days at 15°C , lasting for about 10-14 days under field conditions in central India.

    Adults are stout bodied moths, greenish yellow to buff to brown with darker brown or blackish markings. Females are darker than males. Moths have a circadian rhythm starting at dusk, continues through midnight after which it virtually ceases

     

    Weather, beneficial arthropods and entomopathogens are important factors in mortality of the egg  and in early instar stages   besides host plant resistance. Much work has been carried out on the multiplication and release of Trichogramma spp. egg parasitoids but the technique does not seem feasible for intensive production systems. Among the larval parasitoid the lchneumonid Compoletis chloridae,(Uchida) is the most important  against early instar larvae. Tachinids Carcelia illota Curran, Goniopthalmus halli Mesnil. and Paleorixa laxa (Curran) have been recorded on late larval instars of H. armigera.

     

    Insect pathogens, mainly the HNPV( Helicoverpa nuclear polyhedrosis virus) and strains of Bt. (Bacillus thuringiensis) have been in use. A dose of 4.5 X 109  PIBS/ larval equivalents (LE) @ 250 LE/ha was found to be effective for field use. Their use in Helicoverpa control is limited due to the impact of weather especially high temperature. Nomuraea rileyi, a fungal pathogen attacking H. armigera during periods of

    cool weather and epizootics offers promise to prevent the carry-over of this pest between seasons.

     

    Pink Bollworm (Pectinophora gossypiella Saunders)

    It was first recorded in India in 1842 and it spread to other countries of the world through cottonseeds. It is one of the serious pests of cotton throughout the cotton growing parts of India. P. gossypiella attack, lowers quantity of both lint and seeds and also lowers the qualiity of the lint affecting fibre length , fibre bundle strength and micronaire. Pink bollworm attacks all true cottons, cultivated and wild and many species of Abelmoschus, belonging to Malvales.

     

    Eggs are pearly iridescent white, flattened, oval measuring approximately 0.5 mm long, 0.25 mm wide and sculptured with longitudinal lines. They are laid singly or in small groups of four to five. Early in the season, eggs are laid in any of the sheltered places of the plant axis of petioles or peduncles, the underside of young leaves, on buds or flowers. Once the bolls are 15 days old, these become favored.

    sites for oviposition. Incubation period is 3-6 days. First two instars are white, while from third instar pink colour develops. Larva when attacks buds of less than 10 days old, shedding of bud occurs and larva dies. But with older bud larva can complete development. There can be cent percent pink bollworm infestation on bolls but there need not be any shedding. Larva in flower bud spins webbing that prevents proper flower opening leading to “ rosetted-bloom”. Ten to twenty days old bolls are attacked from under bracteoles. Larvae feed on the developing seeds. While in younger bolls entire content may be destroyed, in older bolls development could be completed on three four seeds. Interloculi movement is also seen. Several larvae can infest a single boll. Larval cycle lasts for 9-14 days in hotter regions.

    The mature larvae are either ‘short-cycle’and will go on to pupate or ‘long cycle’ to enter a state of diapause. While the former is the observed phenomenon in south India, diapause is seen in the north and central parts of India. Short cycle larvae pupating may cut a round exit hole through carpel wall and fall to ground or may tunnel the cuticle, leaving it as a transparent window and pupate inside. Pupation is inside a loose fitting cocoon with a highly webbed exit at one end. Pupal period ranges between 8 and 13 days. The long cycle larvae entering diapanse spins a tough thick walled, closely woven, spherical cell referred as “ hibernaculum” with no exit hole.

     

    Always, the long term larvae occur during end of crop season, where there are mature bolls present and larvae often form their hibernaculae inside seeds. Hibernacula may occupy single seeds or double seeds. Diapause larvae often spin up in the lint of an open boll and if still active in ginnery, will spin up on bales of lint, bags of seed or in cracks and crevices.

     

    The adult moth is greyish brown with blackish bands on the forewings, hind wings are silvery grey. Moths emerge from pupae in the morning or in the evening, but are nocturnal, hiding amongst soil debris or cracks during the day.

     

    Large number of parasitoids and predators are reported attacking pink bollworm. However, majority of them are mere records with their bio-ecology still unknown. Apanteles angaleti carries over in another host (Santhbrota simplex Wism.) in cotton sticks, Chelonus sp. and Camptothlipsis sp. were associated with long cycle pink bollworm larvae (Shekhom and Varma, 1983) and C. blackburni Cam. Was reported as overwintering. Mass rearing and release of various parasitoids from India include Trichogramma brasiliensis (Ashm.), Bracon kirkpatricki and Chelonus blackburni .

    Different predators of Cotton pests are present which are listed below.
         
    1. Lady bird beetle Aphid
    2. Chrysopa Bollworms, Thrips, Whitefly
    3. Assassin Bug Sucking Bollworm Larvae
    4. Syrphid fly Aphid
    5. Spider Bollworm Eggs & Larvae
    6. Pirate bug Sucking Pests Egg & nymph
    7. Orius bug White Fly nymph & Adult
    8. Big eyed bug Sucking Pests Eggs & nymph
    9. Trichogramma Destroys American Bollworm Eggs

    Predatory mites Pyemotes ventricosus (Newport) and P. herfsi (Oudemans) are widely reported as preying on and giving good control of long cycle larvae. Taneja and Jayaswal (1981) determined the capture threshold of male moths in traps with glossyplure for timing the insecticidal application. They found that for effective and economic control of P.gossypiella, insecticides should be applied within 24-48 hours. when the number of male moths captured in traps reaches   eight/trap/night. Surulivelu (1985) found that hand pinning of gossyplure filled hollow fibre on the terminal leaf of cotton plant @ 2.85g/ha reduced the abundance of male moths and reduced infestation by 23.1%.

     

    Cotton Stainers

    Stainers are the only insects that attacks previously undamaged cotton seeds in the field, on any scale. There are two stainer bugs, viz. the common stainer bugs Dysdercus and the cotton seed bugs Oxycarenus. All  the  active stages  of  these bugs  feed  on  the  seed  in  open  bolls  and  reduce the germinating capacity and the seed oil content.

     

    Red cotton bugs (Dysdercus cingulatus Fabricius)

    Dysdercus singulatus nymph and adults feed on developing or mature seeds. Penetration of developing cotton bolls leads to occasional transmission of fungi which develop on the immature lint and seed, rendering the latter unviable and staining the lint to the typical yellow colour. Nymphs and adults are brightly coloured with red head with a white prothoracic collar. Membrane of the hemi-elytron is dark and on the broadest part of the forewing is a black mark as a spot. Eggs are laid in shallow depression in soil or under debris in batches. The nymphal instars are gregarious and feeding is in congregation. Third and subsequent instars can penetrate unopened fruit to feed on developing seeds. Rate of development of egg and five nymphal instars is temperature and nutrition dependent.

    Although mite Hemipteroseius indicus (Lerontz and Knot) has been recorded on D. koenigii (Fabricius) ,

    role of natural enemies appears to be insignificant in controlling cotton stainer numbers.

     

    Dusky Cotton Bug (Oxycarenus hyalipennis, Costa)

    They are lygus bugs associated with ripe seeds of cotton. Adults are small-elongated bugs with pointed heads, dull black to very dark brown. The hemielytra has a translucent dusky appearance. All stages are characterized by a powerful smell when crushed. They feed on seeds and large numbers can reduce weight and viability of seeds. Bugs can discolour the lint if crushed and so are sometimes referred as dusky cotton stainers. Early harvesting minimizes damage.

     

    Foliage Feeders

    Great majority of leaf feeders are chewing insects; mostly lepidopterous larvae, ash weevils and grass hoppers. Lepidopterans are sufficiently extensive at times causing defoliation, thus affecting the photosynthetic efficiency of the plant.

     

    Cotton Semilooper (Anomis flava Fabricius)

    Outbreak of Anomis flava are often sporadic. Larval feeding results in significant loss of leaf area when the plants are young. Larvae are long, slender and green with faint whitish longitudinal lines on the sides and can be distinguished by their looping action.

     

    Looper eggs may be deposited anywhere on the cotton plant, but larvae are usually found on the lower leaf surface and are most likely to be observed on the upper third of the plant. Upon hatching these larvae drop to the older leaves, where small larvae make a window like holes by feeding on the lower leaf surface . By mid growth stage, looper larvae become gross leaf feeders consuming everything but larger leaf vein. Feeding of squares by the larvae is rarely noticed. Tachinid parasite Paliorixa laxa and fungal pathogen Nomuraea rileyi keeps the looper population under control in areas where broad spectrum insecticides have not been widely used.

     

    Cotton Leaf Roller (Syllepte derogata Fabricius)

    It is commonly found in rainfed cotton growing areas, higher infestations occur in shady and weedy conditions. Larvae are seen in groups during initial stages in folded leaves amidst fecal material. Late/last instar larvae move out and pupate individually. The larvae are greenish white and semi translucent, roll up leaves to protect while feeding. Brown pupae is typical in having 8 short spines with hooked tips at their extremity. Moth is light cream with wings transversed with brown / black wavy lines and a black border with greyish fringe. Head and thorax are dotted black and abdomen has brown rings.

     

    Ash Weevil (Myllocerus maculosus)

    It is commonly referred as grey or ash weevil which feeds on leaves, bracts and its larvae feed on roots. Although root damage by larvae can kill young seedlings and cause wilting, adult do not cause significant yield losses.

    All Pakistan Central Cotton Committee Held

    Federal Minister for National food Security and Research Sikander Hayat Bosan Chaired the 86th Meeting of all Pakistan Central Committee held here on Wednesday at Ministry of National Food Security and Research,before devolution this committee was dealt under Ministry of Agriculture /National Food Security

    ISLAMABAD, (agrinfobank.com.pk – 24 May, 2018 ) :Federal Minister for National food Security and Research Sikander Hayat Bosan Chaired the 86th Meeting of all pakistan Central Committee held here on Wednesday at Ministry of National Food Security and Research,before devolution this committee was dealt under Ministry of Agriculture /National Food Security.

    Prime Minister of Pakistan recently placed it again under our ministry, told Federal Minister, said a press release here . He further highlighted that cotton is an important crop but unfortunately it is not given due importance.

    It was my desire to deal this issue under my ministry to take some positive steps for its growth before end of my tenure. This cabinet provided a great support for this crop. He also said that there are certain issue faced by this crop including water shortage, increase in prices of pesticides.

    He also said that 18th amendment could not brought results, which were expected. He also instructed to complete all procedure quickly for better functioning of this committee.

    The Secretary Ministry of National Food Security Mr.Fazal Abbas said that I sent letter to Indus River System Authority to release more water while sowing season.

    IRSA responded that we distribute water to provinces then provincial irrigation departments further distribute waters. He suggested holding meeting with provincial irrigation departments to discuss this issue.

    The Pakistan Central committee discussed twelve agendas including, confirmation of the minutes of the 85th meeting of the committee, approval of revised estimates 2017-2018 and budget estimates for 2018-2019,approval of draft advertisements for appointment to the critical vacant posts of PCCC.

    The meeting was attended by representatives of Ministry of Textile, Ministry of Planning, Chairman Pakistan Agriculture Research Council, Grower member of Baluchistan and official of Ministry of National Food Security and Research.

     

    Central Cotton Research Institute (CCRI), World Wildlife Fund (WWF) Sign MoU For Safe Agriculture Practices, Clean Environment For Wildlife

    Central Cotton Research Institute (CCRI) Multan and World Wildlife Fund (WWF) Pakistan Tuesday signed a memorandum of understanding (MoU) to promote profitable cotton cultivation techniques from boll to bail in a way that it does not hurt natural habitat of wildlife

    MULTAN, (agrinfobank.com.pk – 22nd May, 2018 ) :Central Cotton Research Institute (CCRI) Multan and World Wildlife Fund (WWF) pakistan Tuesday signed a memorandum of understanding (MoU) to promote profitable cotton cultivation techniques from boll to bail in a way that it does not hurt natural habitat of wildlife.

    CCRI Multan director Dr. Zahid Mahmood and WWF-Pakistan senior manager Asad Imran signed the MoU in a simple ceremony here, CCRI spokesman said in a statement. Head of fibre technology section CCRI Multan Muhammad Ilyas said that WWF had been working on a variety of initiatives mainly focused on environment conservation.

    Agriculture practices has an impact on environment and sensing that cotton was one of the most cultivated crops, WWF registered over 100,000 cotton farmers under its various programmes to enlighten them on how to adopt practices that are not only high yielding but also keep environment safe.

    For example, CCRI and WWF experts can tell farmers that they can reduce pesticides application to avoid harm to friendly pests and the environment. CCRI also has a large number of cotrton farmers registered with it.

    Director CCRI Dr. Zahid Mahmood said, the joint venture would enable experts from both sides to address a larger segment of cotton farmers in Pakistan to guide them on cotton crop’s modern and profitable technology, their training for picking, ginning and maintaining fibre quality and publishing material in the form of pamphlets and booklets.

    Under MoU CCRI would extend technical support to WWF to promote modern agriculture practices that are safer for natural habitat of wildlife. The initiative would hopefully help address issues behind low cotton cultivated area recorded last year.

    WWF-Pakistan senior manager Asad Imran promised cooperation to address cotton-related issues of the country and improve environment for wildlife.