Guava it’s Diseases and their Management

Guava it’s Diseases and their Management

Guava (Psidium guajava L.) is an important fruit of subtropical countries. It is hardy crop and is cultivated successfully even in neglected soils. It is a small or shrub like evergreen tree. It has slander like trunk with smooth red green bark. Oval shape fruit green to yellow in color. Its   height is about 33ft and life span is approximately 40years. Pakistan is second largest guava producing country. According to (PCRSC) survey of Pakistan (2015-16) 70026 hectare area under guava cultivation and its production is 414649 tons annually. Some major and impressive guava benefits on human health are; it manage blood pressure, help in digestion, weight loss, improve immunity system, healthy eyes, prevent from cancer. There are number of pathogens, mainly fungi, which affect the guava crop besides few bacterial, algal and some physiological disorder.  About 177 pathogens of which 167 are fungal 3 bacterial, 3 Algal, 3 Nematode and 1 apiphyte. These pathogen causes different type of diseases in guava plant at different stages from growing stage to maturity and fruiting time. Postharvest and fruit diseases are also important which cause serious losses. Fruit disease have also two types i.e.; field disease and postharvest, which develop during storage and transit. In the present communication some major diseases are describe with their symptom and disease management practices.

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Diseases Symptoms, survival and spread, Favourable condition and their management:

Guava Wilt:

Diseases Symptoms:

Muhammad Abdul Rehman

Department of Horticulture, College of Agriculture, University of Sargodha

  • In this diseases pathogen mostly attack young as well as old fruit bearing trees
  • Symptoms mostly start with the on fall of monsoon appearance of light foliage with the loss of epinesty & turgity
  • Roots of the plant also show rooting at the basel region
  • Bark of the plant can be easily detachable from the cortex
  • Light browned blotch can also be observed in vascular tissue

 Favourable Conditions:

  • Highly rainfall during Aug-Sep
  • For long duration stagnation of water in guava field
  • RH 76% are conducive with min to max temperature range (23-32°c)

Spread & Survival:

  • Mostly spread by water in short distance
  • Wild disease can also be predisposes through root injury

Management:

  • We can manage the disease through proper sanitation.
  • Through solarization of the soil.
  • Burnt wilted plants and uprooted.
  • Treat guava plant with 0.1% water soluble 8 quinolinol sulphate .it may provide protection to the plant for at least 1 year against wilt.
  • Harsh pruning followed by a drench with 0.2% Bavistine or Benlate 4time in a year.

Fruit Rot:

Disease Symptoms:

  • In this disease mostly start of calyx disease of fruit during raining season
  •  The fruit near soil level coverall with dense foliage are mostly effected under high relative humidity
  • With cotton like growth covered the inffected area which develops very fast as fruit matures. Pathogen can be able to cover the entire surface during the humid weather within a period of 3-4 days
  • Fruit skin below the whitish cottony growth become a little soft, turn light brown to dark.

Favourable condition:

  • Poorly drained soil and injured, high humidity, temperature from (28-32°c) favourable for the iniation of disease
  • High soil moisture, cool, wet enviormental condition favourable  to disease development

Spread and Survival:

  • Greet no of sporangia and spores can be produce on the surface of diseased tissues principally by pathogen when temperature  near to 25°c
  • Spores can also be spread through infected plant material or soil by rain splashes

Management:

  • Kothari (1968) recommended weekly spray of Bordeaux mixture and copper oxychloride.
  • Management of dry rot through the use of fungicides like Ziride 0.3%.
  • Seed treatment with Bavistin 3g/kg seed controls the disease effectly.

Fruit canker:

Disease symptoms:

  • The symptoms of this disease occur generally on green fruit and rarely on leave
  • Effected fruit remain under develop, become hard, mummified malformed and drop. Sometime, small rusty brown angular spots appear on the leaves
  • Crater like appearance is more observed on fruit then leaves
  • Margin of lesion is elevated and a depressed area is observed in inside
  • On start minute, circular, unbroken brown necrotic area appear in fruit advance  stage of infection, Tears open the epidermis in a criminate manner

Favourable conditions:

  • Spores germination will be maximize at 30°c and can’t germinate below 15°c or above 40 with RH above 96%

Spread and survival:

  • The pathogen is primary a wound parasite and avoid injury to fruits

Management:

  • Spread disease can be controlled by 3 or 4 spray of 1%of Bordeaux mixture or lime sulphate at 15days interval.
  • Naisk and cultives Sind show good resistance against this disease.
  • Safeda and apple color verities are highly resistant against this disease.
  • The homoeopathic drugs, potassium iodide and arsenic oxide completely inhibited spore germination.it can also inhibit the growth of pathogen.

Algal Leaf & fruits spots:

Diseases Symptoms:

  • In this disease immature guava leaves infect during early spring fall
  • On the leaves minute, shallow brown lesion appear especially on the tip of leaf, areas or margins adjacent the mid vein and as the disease advance, lesion in large in diameter from 2-3mm
  • The spot on the leave may vary from specks to big patches which may be scattered or crowded
  • The lesion on immature fruit are nearly black, lesion get sunken & cracked frequently as fruit enlarge
  • Lesion are smaller than leaf spot. They convert their color from darkish green to black

Favourable conditions:

  • By splashing water zoospore spread
  • Disease can also spread through humid wet condition

Spread and survival:

  • Air borne diseases mostly spread through air or rain splashes
  • On the infected plant debris pathogen survive

Management:

  • High sanitation required because algae can survive on fallen leaves during winter.
  • Discard of infected debris carefully to prevent spread of disease.
  • Prune plants to improve air circulation and excess of sunlight.
  • Avoid wetting of leaves as much give water at the base of the plant.
  • Apply Bordeaux mixture or copper based fungicides if plant seriously infected.

Stem canker & Dry fruit rot:

Diseases Symptoms:

  • In this disease pathogen mostly attack on main branches & stem on which it causes cracking of lesions
  • In perfect stage diplodia netalensis dry fruit rot, Physalopara psidii causes stem canker
  • On the infected stem through fungal perithesia small brown to black structure may develop
  • Symptoms appear on the fruits as light brown spots generally at the stalk or calyx end
  • The entire fruit becomes dark brown to black & mummified with 4 days
  • Twing bearing infected fruits show dieback

Favourable Conditions:

  • For disease development rainy season is favourable
  • Humidity & wet condition required

Spread & Survival:

  • Pathogen spread through air from plant to plant
  • Patgogen survives beneath the bark of the plant & become active when condition are Favourable

Management:

  • High sanitation required.
  • Management of dry rot through the use of fungicides like Ziride
  • Mostly recommended spray of Bordeaux mixture and copper oxychloride

Dieback and Anthracnose (Fruit rot)

Disease symptoms:

  • Fruit and leaf infection phase: During rainy season infection can be seen on unripe fruits pinhead spot are first seen which gradually enlarge.
  • In dark brown color spots sunken, circular and have minute black stromata in the center of lesion, in moist weather produce creamy sporemasses.
  • To form bigger lesion several spots coalesie.
  • Infected area of unripe fruits become corky and in case of severe infection often develops cracks.
  • Bud and flowers which are unopened are also effected and cause their shedding.
  • The fungus cause necrotic lesion usually ashy gray and bear fruiting bodies at the tip or on the margin of the leaves.
  • Die back phase: From the top of a branch; plant being to die backwards touxy shoots, leaves and fruits are readily attached. The greenish color of young growing tip change into dark brown and later to black necrotic areas extending backwards.

Favourable conditions:

  • Rain splashes, wind encourage the spore production and its dispersal around the canopy.
  • Without canopy management closer planting
  • Temperature between (10-35°c) with best of (24-28°c).

Spread and survival:

  • Through infected foliage moment of plant material.
  • By wind borne spores develop on dead leaves, twigs and mummified in the orchard infection spreads.
  • Transportation of fruits through high disease prone area.

Management:

  • Apply streptosporangium pseudovulgare before appearing symptoms.
  • Spray copper oxychloride 50%WP @ 4gm/lit.

To conclude the above mentioned are some major diseases of guava. Guava is an important fruit crop of Pakistan and grown on large scale. It is an economic fruit that provides good income to the growers. It is a nutrient-dense super food and provides much health benefits to humans. But due to attack of diseases on this nutritious fruit crop as well as due to lack of knowledge among farmers about disease management annual losses are quiet high. So, we should have to give proper care to guava crop regarding disease management if we want to take benefits from this in future.

Plant Defended Mechanism towards Pathogen

Plants, also called green plants are multicellular , autotrophic eukaryotes of the kingdom plantae.

Major plant pathogen

Bacteria

Virus

Fungi

Nematodes

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When pathogen attack on plants the genes of pathogen are activated (produce all their weapons of attack e:g enzymes, toxin etc).

Hafiz Muhammad Rizwan Mazhar

                  Department of Plant Pathology, University of Agriculture, Faisalabad-Pakistan

                                             (E-mail: rizwanmazhar084@gmail.com)

Plant show Resistance in Different Ways

Polygenic

Monogenic

Induced

Polygenic Resistance

                                        Many genes include in such type of resistance

Some plant genes code for the chemical substances

Toxic to pathogen or neutralize the toxin of pathogen

Some structural genes also preasant which slow down the entry of pathogen

Plant show resistance partiallt or incompletely

Different genes are involved

Plant pathogen attack

Monogenic, r- gene Resistance

                                                      Have one resistance genes per pathogen capable of attacking it.

Pathogen____ host

A-virulence genes in pathogen

Trigger the R-genes in the host

Host will plant  show the resistance

Induced Resistance

                                          Induced resistance is adefense system within plant which allow them to resist attack from pests such as fungal or bacterial pathogen. The defense system react to the external attack with physiological changes triggered by the generation of proteins and chemicals that lead to activation of plants immune system

Two main types of induced resistane exist

SAR                            ISR

SAR (systemic acquired resistance): occur when a localized wound is created on the plant causing necrosis

ISR(induce systemic resistance): occur when plant roots are colonized by plant growth promoting  rhizobacteria

Effect of viruses on photosynthesis

The most obvious symptom of systemic virus infection is the mosaic pattern of the leaves. Yellowing, chlorosis is also frequent and characteristic sign of the altered photosynthetic activity. Virus infection effects photosynthesis in a complex manner, depending on the particular host-virus combination. The symptoms are basically different in the incompatible or the compatible host-virus interaction. 
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Hafiz Muhammad Rizwan Mazhar

                  Department of Plant Pathology, University of Agriculture, Faisalabad-Pakistan

 

                                             (E-mail: rizwanmazhar0

[/ads-quote-center]84@gmail.com)

Photosynthetic changes in incompatible host-virus interaction Virus infection often causes local lesions in resistant plants. The development of local lesions in hypersensitive reaction (HR) was described in details by electron micros- copy, based on the time course of the appearance of symptoms. The ultrastructure of the lesion and the surrounding cell layers and the role of the active zone in the localisation of the infection was highlighted (Israel and Ross, 1967).

In tobacco mosaic tobamovirus (TMV) infected N. glutinosa leaves the size and number of the starch grains increased in the chloroplasts following the infection (Weintraub and Ragetli, 1964). One day after the infection plasmolysis occurred, and first the cytoplasm and later the chloroplast membranes completely disappeared.

 In the remains of the chloroplasts large vesicles were formed, the number of mitochondria increased and their structure changed. Finally the whole cell structure collapsed and its content disin-tegrated. All these alterations were consequences of the loss of osmotic regulation, and have been related to the so-called ‘starch-lesions’ described by Holmes (1931).

Photosynthetic changes in compatible host-virus interaction For the synthesis of virions the parasite uses the metabolites and energy of the host plant, which are produced in the course of photosynthesis. It is evident that the phy- siological processes of the virus and the plant are linked in complex ways, the structure and the function of the chloroplasts are disturbed (Zaitlin and Hull, 1987).

Changes in the ultrastructure of chloroplasts

The chlorosis of leaf tissues in the compatible host parasite interactions can be traced back to different causes. The number, size or chlorophyll content of the chloroplasts may decrease.Their shape, inner membrane structure may alter to some degrees, some of their metabolites may accumulate. Often the starch grains enlarge, or accumulate for example in the case of the cauliflower mosaic caulimovirus (CaMV) infected cabbage plants (Conti et al., 1972).

Effect of virus infection on CO2-fixation and on some biosynthetic processes 

In several virus-host interactions the disturbances of CO2-fixation and of related metabolic ways, or the alteration in ratio of certain products was reported. At the early stage of systemic TMV infection (virus replication) more CO2molecules assimilated by the photosynthetic processes (Doke and Hirai, 1970a). As the infection had been progressed this tendency inverted: CO2-uptake was decreasing in the infected.

 The same changes as well as the increase of res-piration were observed in tobacco leaves infected with tobacco etch potyvirus (TEV).The enzyme activity of phosphoenol-pyruvate-carbox-ylase (PEP-carboxylase) increased in the leaves of chinese cabbage infected with TYMV.

In contrast, in tobacco leaves infected with TSWV activity loss of PEP-carboxylase was measured and it was explained as the early senescence induced by the virus infection.

Changes in the chlorophyll protein complexes and chloroplast proteins

Virus infected monocotyledons (e.g. barley infected with BSMV or WSMV) contained reduced amount of chlorophyll protein complexes compared to the healthy controls.

Effect of virus infection as a biotic stress factor on photosynthesis

Stress has been described by Osmond et al. (1987) as all parameters that suppress the maximum, potential genomial value of growth and reproduction of a plant. Plants adopt to stress conditions in two ways, either by tolerance or avoidance. In the case of tolerance the plant’s reaction to a moderate stress is the upregulation, while against a severe stress the down regulation of metabolic processes.

At the cellular level the damage in the membranes and the fluorescence of chlorophyll built in the thylakoid membranes indicated the post stress conditions. In the early phase of virus infection both the non-photochemical quenching of fluorescence and the predominantly reduced state of QAthe primary electronacceptor of PSII, indicated the development of symptoms and the rapid chloroplast destruction due to photoinhibitory conditions (Balachandran et al., 1997).

 

 The build up of carbohydrates and the brakeup of the equilibrium between synthesis and brakedown probably blocks the gen regulation, which effects the level of chlorophyll-protein complexes and photosynthetic metabolic enzymes.

 

Alfalfa Sprout Rot

Alfalfa Sprout Rot

Cause.

Erwinia chrysanthemi survives for up to 2 weeks on inoculated dried seeds. Air, the water supply, or greenhouse workers may introduce bacteria into a sprouting house. Spread within a tray is by seed to seed contact. Rot is most severe at high moisture and temperatures of 28°C and above. Little disease occurs below 21°C.

Symptoms.

Radicles are a translucent yellow as they emerge from the seed. In 24 to 48 hours, seeds stop growing and turn into a yellowish, odiferous mass that contains numerous bacteria. Disease initially occurs in a few trays, but it may spread throughout all trays in a few days.

Management

1. Control temperature in the sprouting house.

2. Practice sanitation. Bacteria likely survive in water remaining in tanks used for soaking seeds.

3. Soak seeds for 2 hours in 0.5% sodium hypochlorite or calcium hypochlorite. However, hypochlorite is not currently registered for alfalfa seed treatment in the United States.

20 Common Tomato Plant Problems and How to Fix Them

If you’re one of the three million people who planted a home garden this year, you’re most likely growing tomatoes. Nine out of 10 gardeners grow tomatoes, and that number would be 10 out of 10 if the holdouts would taste a fresh garden tomato and compare it to a grocery store purchase. Nothing beats the taste of a fresh home-grown.

Many gardeners who grow tomatoes, however, are frustrated with the progress of their plants. The plant may not set fruit. Or your tomatoes may ripen, but have ugly, spongy black spots at the bottom. Worse still, your plants may look great in the evening when you say goodnight to them, but in the morning, they’re skeletons waving empty branches in the breeze.

Welcome to the world of tomato problems. This list of 20 common tomato problems and their solutions will help you identify an issue — whether it’s just starting or already full-blown — and show you how to correct it, so you can save your tomato plants and harvest yummy tomatoes this year.

IDENTIFY TOMATO PLANT PROBLEMS AND DISEASES

Before diving into the list, it’s important for you to correctly identify the problem or tomato plant disease. When trying to identify tomato plant diseases, use these steps:

  1. Identify the affected part of the plant — Is it the tomato itself, the leaves, stems, flowers or roots?
  2. Note differences — When you compare your tomato plant to a healthy plant, how does yours differ? For example, a healthy tomato plant has softly fuzzed, medium-green leaves. If the leaves of your plant have brown or black patches, holes, chewed edges or fuzzy mold growing on them, make a note of that before perusing the list of problems.
  3. Look for insects — What insects do you see on your plants? If you need help identifying them, take a photo and contact your local Cooperative Extension agent to identify the insects.

Armed with this information, you can easily scan this list and narrow down the possible tomato plant disease or pest problem and how to fix it.

20 COMMON TOMATO PROBLEMS

The list is divided into two sections: 16 diseases caused by poor cultivation habits, bacteria or fungi, and 5 insect-specific tomato problems. We have also included some tips for growing delicious, healthy tomato plants so you can keep those problems away next year.

16 TOMATO PLANT DISEASES

Tomato diseases, garden fungi and certain environmental conditions can quickly cripple your plants. Oftentimes, you can rescue the tomato plant with a little TLC, but some circumstances may require you to destroy the plant and plant another crop in its place.

Help for tomato plants

Be sure to browse the extended information below on tomato plant problems, but, overall, here are the most common disease and fungus triggers in tomato plants:

  • Not enough fertilizer. (Solution: Test your soil and apply fertilizer as appropriate for the growth stage.)
  • Over-pruning. (Solution: Always use a tomato cage and leave enough foliage to shield the fruit.)
  • Not enough calcium. (Solution: Test your soil, apply lime and gypsum as needed.)
  • Planting before temperatures raise to ideal levels. (Solution: Wait for the right planting time for your Hardiness Zone.)
  • Too much water or too little water. (Solution: Water them evenly through the growing season.)
  • Watering overhead, which promotes fungal growths. (Solution: Water at the base of the plant. and apply fungicide.)
  • Lack of air flow around plants. (Solution: When planting, space tomato plants at appropriate distance from one another and prune leaves (but not too much, see above) as they grow. Apply  fungicide if powdery mildew appears.)

what does blossom end rot look like on tomatoes

1. Blossom End Rot

  • What it looks like: The tomato plants appear healthy, but as the tomatoes ripen, an ugly black patch appears on the bottoms. The black spots on tomatoes look leathery. When you try to cut off the patch to eat the tomato, the fruit inside looks mealy.
  • What causes it: Your plants aren’t getting enough calcium. There’s either not enough calcium in the soil, or the pH is too low for the plant to absorb the calcium available. Tomatoes need a soil pH around 6.5 in order to grow properly. This soil pH level also makes it possible for them to absorb calcium. Uneven watering habits also contribute to this problem. Hot, dry spells tend to exacerbate blossom end rot.
  • What to do about it: Before planting tomatoes in the spring, have your local garden center or Cooperative Extension conduct a soil test. Tell them you’ve had problems with blossom end rot in the past, and they will give you recommendations on the amendments to add to your soil. Lime and gypsum may be added for calcium, but they must be added in the proper amounts depending on your soil’s condition. That’s why a soil test is necessary. Adding crushed eggshells to your compost pile can also boost calcium naturally when you add compost to the soil. A foliar spray containing calcium chloride can prevent blossom end rot from developing on tomatoes mid-season. Apply it early in the morning or late in the day — if sprayed onto leaves midday, it can burn them. Water plants regularly at the same time daily to ensure even application of water.

blossom drop on tomato plants

 2. Blossom Drop

  • What it looks like: Flowers appear on your tomato plants, but they fall off without tomatoes developing.
  • What causes it: Temperature fluctuations cause blossom drop. Tomatoes need night temperatures between 55 to 75 degrees F in order to retain their flowers. If the temperatures fall outside this range, blossom drop occurs. Other reasons for blossom drop on tomatoes are insect damage, lack of water, too much or too little nitrogen, and lack of pollination.
  • What to do about it: While you can’t change the weather, you can make sure the rest of the plant is strong by using fertilizer for tomatoes, drawing pollinators by planting milkweed and cosmos, and using neem oil insecticides.

 why are my tomatoes cracking

3. Fruit Cracks

  • What they look like: Cracks appear on ripe tomatoes, usually in concentric circles. Sometimes insects use the cracks as an opportunity to eat the fruit, or birds attack cracked fruit.
  • What causes them: Hot, rainy weather causes fruit crack. After a long dry spell, tomatoes are thirsty. Plants may take up water rapidly after the first heavy rainfall, which swells the fruit and causes it to crack.
  • What to do about them: Although you can’t control the rain, you can water tomatoes evenly during the growing season. This prevents them from being so thirsty that they take up too much rainwater during a heavy downpour.

 

what does sunscald on tomatoes look like

 4. Sunscald

  • What it looks like: The plants look healthy, and the fruit develops normally. As tomatoes ripen, yellow patches form on the red skin. Yellow patches turn white and paper-thin, creating an unpleasant appearance and poor taste.
  • What causes it: As the name implies, the sun’s rays have actually scalded the tomato.
  • What to do about it: Tomato cages, or a wire support system that surrounds the plants, give the best branch support while shading the developing tomatoes naturally. Sunscald usually occurs on staked plants that have been too-vigorously pruned, exposing many of the tomatoes to the sun’s rays. Leaving some foliage and branches provides shade during the hottest part of the day.

 

Poor Fruit Set - Why are my tomatoes not growing

 5. Poor Fruit Set

  • What it looks like: You have some flowers but not many tomatoes. The tomatoes you do have on the plant are small or tasteless.
  • What causes it: Too much nitrogen in the soil encourages plenty of green leaves but not many flowers. If there aren’t enough flowers, there won’t be enough tomatoes. Another cause may be planting tomatoes too closely together. Tomatoes are self-pollinating, meaning that each flower contains both the male (stamens) and female (pistils) parts. Wind typically pollinates tomatoes, but if plants are too close together, the wind can’t reach the flowers.
  • What to do about it: Have your soil tested. If you’re planting tomatoes in the spring, leave at least two feet or more between plants so that good air circulation can help pollinate them. If your plants are already in the garden, you can simply shake the flowering branches to simulate wind and get the pollen from the stamens to the pistils.

 

catfacing tomato

 6. Catfacing

  • What it looks like: Catfacing makes tomatoes appear deformed. The blossom end is rippled, bumpy and lumpy.
  • What causes it: Plants pollinated during cool evenings, when the temperatures hover around 50 to 55 degrees F, are subject to catfacing. Blossoms fall off when temperatures drop too low. However, if the flower is pollinating before the petals begin to drop off, some stick to the developing tomato. This creates the lumps and bumps typical of catfacing.
  • What to do about it: If possible, plant tomatoes a little later in the season. Make sure the weather has truly warmed up enough to support proper tomato development. Devices such as a “Wall of Water” — a circle of water-filled plastic tubes — raise temperatures near the tomato and help keep them high enough on cold nights to prevent cold-related problems. Using black-plastic spread on the soil can also help. As the plastic heats during the day, it releases the heat back towards the plants at night. Black plastic can be used as a temporary measure until the temperatures warm up enough that it’s no longer needed.

 

Why are my tomato plant leaves rolling and shriveling up

 7. Leaf Roll

  • What it looks like: Mature tomato plants suddenly curl their leaves, especially older leaves near the bottom. Leaves roll up from the outside towards the center. Sometimes up to 75% of the plant is affected.
  • What causes it: High temperatures, wet soil and too much pruning often result in leaf roll.
  • What to do about it: Although it looks ugly, leaf roll won’t affect tomato development, so you will still get edible tomatoes from your plants. Avoid over-pruning and make sure the soil drains excess water away.

 

tomatoes look normal but gaps inside

 8. Puffiness

  • What it looks like: The tomato plants look fine, they bloom according to schedule, and ripe red tomatoes are ready for harvest. When the tomato is sliced, the interior has large, open spaces and not much fruit inside. Tomatoes may feel light when harvested. The exterior of the tomato may have an angular, square-sided look.
  • What causes it: Under-fertilization, poor soil nutrition or inadequate pollination.
  • What to do about it: Make sure you are feeding your tomato plants throughout the season. A balanced fertilizer such as a 10-10-10 should be fed biweekly or monthly. Tomatoes are heavy feeders and need fertilizer throughout the growing season. For gardeners, frequent top-dressings with homemade compost and compost teas are a must.

 

tomato plant disease - bacterial canker

 9. Bacterial Canker

  • What it looks like: Often confused with cloudy spot disease, bacterial cankers start as yellow dots on ripening red tomatoes. If you look carefully at the spots — using a magnifying glass if you have one — you’ll see a dark, birds-eye-type rim around each of the yellowed spots. This is what distinguishes bacterial canker from cloudy spot disease.
  • What causes it: A bacteria called Clavibacter michiganensis. The bacteria occurs naturally but can be brought into the garden on infected plants or tools. Once it gets into the soil, rainwater splashes it up onto the plants. If there’s an open sore, such as insect damage or a leaf missing from pruning, it can enter the plant and infest it.
  • What to do about it: Remove the infected plants immediately and do not plant tomatoes again in that soil for at least three years. Rotate your crops regularly to prevent these and other diseases from taking hold in the soil. Don’t compost the dead plants — instead, put them in the trash to avoid spreading the bacteria.

 

Anthracnose - dark mushy spot on tomatoes

10. Anthracnose

  • What it looks like: As tomatoes ripen, a dark, bull’s-eye circle appears on the blossom end or bottom of the tomato. The spot is sunken and mushy to the touch. When you slice into the tomato, there’s a black mushy spot underneath that looks like rot.
  • What causes it: A fungus called Colletotrichum phomoides. The fungus loves hot, moist weather and is often spread by overhead irrigation, sprinklers striking infected soil and splashing the fungus up onto the plants, and infected plants.
  • What to do about it: Switch your watering methods so water drips on the roots, not the leaves of the plants. Harvest tomatoes when ripe, since overly ripe tomatoes tend to contract the fungus more than tomatoes in the early stages of ripening.

 

early blight on tomatoes

 11. Early Blight

  • What it looks like: You’ll find brown spots on tomato leaves, starting with the older ones. Each spot starts to develop rings, like a target. Leaves turn yellow around the brown spots, then the entire leaf turns brown and falls off. Eventually the plant may have few, if any, leaves.
  • What causes it: A fungus called Alternaria solani. This fungus can live in the soil over the winter, so if your plants have had problems before like this, and you’ve planted tomatoes in the exact same spot, chances are good the same thing will happen to your plants this year.
  • What to do about it: Crop rotation prevents new plants from contracting the disease. Avoid planting tomatoes, eggplants or peppers in the same spot each year as these can all be infected with early blight. A garden fungicide can treat infected plants.

 

Tomato fungus - Septoria Leaf Spot

 12. Septoria Leaf Spot

  • What it looks like: After the plants begin to develop tomatoes, the lower leaves break out in yellow spots. Within the yellow spots, dark gray centers with dark borders appear. Black dots appear in the center of the spots. Foliage dies and falls off.
  • What causes it: A fungus called Septoria lycopersici thatinfects foliage.
  • What to do about it: Avoid watering tomatoes from the top, as the spray can force the spores developing on the leaves back into the soil and continue the disease cycle. Certis Double Nickel 55™ Fungicide & Bactericide was developed for use against Septoria Leaf Spot on tomatoes.

wilted tomato plant fungus

13. Fusarium Wilt

  • What it looks like: Your tomato plants look fine, when suddenly, they start to wilt. At first, only one side may be affected, but then the whole plant is wilting. You water them, and the problem gets worse. Within a day or two, the plant is dead!
  • What causes it: A nasty fungus called Fusarium oxysporum f.sp. lycopersici that attacks the vascular system of the plant, roughly equivalent to a human’s veins. The fungus destroys the xylem tubes, which transport water and nutrients up from the roots and into the leaves.
  • What to do about it: In the case of fusarium wilt, the best defense is a good offense. Rotate your crops so tomatoes aren’t planted in the same section of the garden each year. Purchase wilt-resistant varieties if you’ve lost tomatoes to wilting diseases in the past, since the fungus can overwinter in garden and lawn soils.

Verticillium Wilt - Tomato plant fungus with yellow spots on leaves

 14. Verticillium Wilt

  • What it looks like: Yellow blotches appear on the lower leaves. As the blotches spread, the veins in the leaves turn brown. After the leaves turn brown, they fall off. The disease progresses up the stem until the plant is stunted.
  • What causes it: A fungus that lives in the soil, Verticilliurn albo-atrum, attacks the roots and travels up the xylem tubes with water. It then prevents the normal flow of water and nutrients to the leaves.
  • What to do about it: Once plants are infected, there isn’t much you can do to treat Verticillium wilt. Rotate your crops, because the fungus can live for long periods in the soil and even live among weeds such as ragweed. Choosing wilt-resistant varieties to plant is the best way to prevent Verticillium wilt.

What wrong with my tomatoes - spotted wilt virus

 15. Viral Diseases

  • What they looks like: Viral diseases mainly attack the tomatoes themselves. You might find black spots on tomatoes, or weird stripes on them. Don’t confuse signs of disease for just how some heirloom tomatoes look with natural stripes.
  • What causes them: Many of these viruses spread when plants are stressed by heat, drought or poor soil.
  • What to do about them: If you’ve read through all of these tomato problems and think your tomatoes may be suffering from a viral disease, spray your tomato plants with neem oil. Good soil management and using organic fertilizer for tomatoes also helps keep your plants healthy, which can help them naturally resist viruses better.

 

powdery mildew on tomato leaves

16. Powdery Mildew On Tomatoes

  • What it looks like: Powdery mildew is easy to find on tomato plants as it looks like someone brushed the leaves with a white powder. You might find white spots on tomato leaves or even the stem. If you let the fungi thrive it will turn your tomato leaves yellow and then brown.
  • What causes it: Powdery mildew on tomatoes is more common in greenhouses than an outdoor garden because of the lack of air flow and high humidity.
  • What to do about it: The best way to prevent powdery mildew on tomato plants is to use a preventative spray formulated with sulfur. For more information, read this post on prevention and treatment of powdery mildew on plants.

5 INSECTS THAT CAN DESTROY YOUR TOMATOES

In addition to diseases, insects can damage tomato plants, too. Not all bugs are bad — some insects are extremely helpful, and some will even attack the “bad” bugs plaguing your tomato plants.

Help for tomato plants

Be sure to browse the extended information on tomato plant pests below, but, overall, here are your best options for fighting insect infestations on tomato plants:

  • Caterpillar Killer with B.t. (Solution: Fight hornworms and other plant-eating caterpillars with this OMRI Listed® biological control that targets destructive larvae.)
  • Insect Killing Spray for Tomatoes. (Solution: An insect-killing formula for use on tomatoes that’s compliant for use with organic gardening and fights tomato hornworm, Colorado potato beetles, whiteflies and other caterpillars.)
  • Insecticidal Soap. (Solution: An OMRI Listed® insecticide soap that can be used up to the day of harvest on aphids, mealybugs, spider mites and other pests.)
  • Insecticidal Soap with Pyrethrin. (Solution: By mixing the features of insecticidal soap and pyrethrin, you can maintain your organic garden and fight spider mites, hornworms and destructive beetles.)
  • Neem Oil. (Solution: Neem oil kills insects in every life stage — from eggs to adults.)
  • Insect Traps. (Solution: Lure pest insects away from your plants and trap them before they can do more damage.)

The following tend to be the most common causes of various tomato pest problems.

cutworms on tomatoes

1. Cutworms

  • What they are: Cutworms feed at night on seedlings. They “cut” or eat through the stem at soil level or an inch or less above the soil. Cutworms aren’t exactly worms — they are the larvae of certain moths. They only emerge at night and can be difficult to spot. Cutworms kill tomato plants by snipping them right in half.
  • What to do about them: Prevent cutworm damage by making a paper collar that fits around your seedlings. Just take newspaper or cardboard and fold it into an inch-wide strip. Use tape to make a collar around the plant, leaving about two to three inches around the stem. Remove the collar once the plant has several sets of leaves. You can also cut the bottom off of a paper cup and slide the open-bottom cup over the seedling to prevent cutworm damage.

 

hornworm on tomato plants

 2. Hornworms

  • What they are: Tomato or tobacco hornworms can decimate mature tomato plants in one night. These crafty insects are large green worms about two to three inches long with tiny horns on their head and ridged bodies. Hornworms are perfectly camouflaged so they look exactly like a tomato stem or branch, making them difficult to spot. They emerge at night, eat all the leaves off the plant and move on to the next section or plant.
  • What to do about them: Nature provides the best control for tomato hornworm in the form of a parasitic wasp that lays her eggs on the body of the hornworm. As the wasp’s larvae hatch, they eat into the living worm and eventually kill it. Natural methods to control tomato hornworms include planting marigolds around tomatoes. The strong marigold scent repels them naturally. Safer® Brand Caterpillar Killer II With B.T. uses a naturally occurring fungus to quell hornworms without harming earthworms. You can also use an insect-killing spray.

 

Colorado potato beetle damaging tomato plants

 3. Colorado Potato Beetle

  • What they are: Colorado potato beetles are native to the United States. They love plants in the nightshade family, especially potatoes. If they can’t find potatoes, however, they will gravitate towards tomatoes, eggplant and other nightshade family vegetables. The beetles are about the size of dimes, with yellow-and-black striped wings. The adults use their mouthparts to chew holes in the leaves of tomato plants. Females lay clusters of bright gold or yellow eggs underneath the leaves. When the larvae hatch, they spread out among the tomato leaves, easily eating their way through the entire plant. Larvae are red to dark pink with black spots and frequently hide under the leaves during the day.
  • What to do about them: Use a pesticide with pyrethrins to spray on your tomato plants. This method works best in early spring before the larvae mature.

how to get rid of stink bugs on tomato plants

4. Stink Bugs

  • What they are: The brown marmorated stink bug isn’t only an annoyance inside the home. These insects also use their needle-like mouthparts to suck the juice right out of your tomatoes. They can be spotted with the naked eye on your tomatoes, or you can see their damage in the yellow, uneven spots that appear on the ripening tomatoes. When you slice into a yellow-spotted tomato, white sections appear under the yellow spots, which distinguish stink bug damage from fungal or viral problems.
  • What to do about them: Safer® Brand makes stink bug traps that harmlessly attract the insects to the trap and away from your tomatoes.

 

how to get rid of spidermites on tomatoes

5. Spider Mites

  • What they are: Spider mites are difficult to see because they’re so tiny, but you can clearly see the damage they leave behind. Mites scuttle along the stems and leaves, piercing the leaves to feed on the juices. Eventually, tomato leaves look stippled and bronzed, with damage to the plant’s leaf structure.
  • What to do about them: The best method for treating spider mites on tomato plants is to use a neem oil spray. Another option is insecticidal soap, which also offers a treatment for spider mites.

NOT JUST BUGS: BIRD PROBLEMS

One final tomato problem is often mistaken for insect damage: birds. Some birds, especially crows, love to eat ripening fruit, and tomatoes are technically a fruit. Crows peck with their large, sharp beaks at the ripening tomatoes, ripping open gashes and eating partial segments from various fruits. Other birds and even squirrels may also be at work if you find tomatoes that look like they have bites taken out of them.

The best control for bird problems is a net. A large fruit tree net, available at your local home or garden store, can be draped over the plants. The net is an effective deterrent to birds and usually a good deterrent for squirrels, too.

Although this list of tomato problems is extensive, don’t let it deter you from growing great tomatoes. The good news is that most of these diseases and problems still leave you with some edible tomatoes. And once you take precautions to avoid these diseases and pests in your future gardens, your tomatoes will continue to be fruitful and successful. 

Source of Article: http://www.saferbrand.com.

Diseases following fresh rainy spell

The Met Office on Tuesday advised farmers to ensure field sanitation and prophylactic fungicidal sprays to safeguard the standing crops from diseases following the fresh rainy spell. “Weeds are expected to shoot in excess after the rains. Farmers should control weeds growth soon after the rains,” the office said in its 10-day advisory for farmers.
Diseases following fresh rainy spellIt said the farmers should halt irrigating their crops since the continuing rainy spell provided sufficient water and asked the growers to plan irrigation keeping in view the likely rain in agricultural plains of the country. “Wheat crop is growing at Heading/Flowering/Milk Maturity stages in most of the agricultural plains of the country,” it said, adding that farmers should step up to control further weeds growth to prevent negative impact on their crops. “Weeds removing practices should be started soon after expected rains in the mentioned areas,” the office said.
It says wheat crop is growing at very crucial development stages of milk maturity/ wax maturity, in Sindh and Punjab province. “Farmers of these areas are advised to irrigate the crops as per requirement keeping expected rains in mind,” it adds. Rainfall/ light snowfall over the hills and over upper and central parts of Punjab is expected in the next 10 days. It forecast rainfall for Sindh at isolated places during first five days of the advisory while dry weather is likely to prevail in its most parts till March 20.
It said rainfall/light snowfall over the hills and over upper and central parts of Khyber Pakhtunkhwa is expected during the period. Rainfall is expected at isolated places of Balochistan during the first five days of the forecast period. In Gilgit-Baltistan, it said mainly cold and cloudy weather is expected in most parts. However, light to moderate rainfall (with snow over the hills) expected at isolated places during the period. In Kashmir, the office said cold and cloudy weather with rainfall/light snowfall over hills is expected in most parts.

Source: Business Recorder 

Sugarcane : A Complete guide

SCIENTIFIC NAME: Saccharum officinarum

INTROUDCITON:

Sugar cane is C4 plant it is a parineal crop. The plant takes 10 to 12 month under Pakistani condition. 18 month under Australian condition and 24 month in Cuba and Brazil condition to complete its life cycle. The plant grows from seed set called as plant crop. It is vegetative plant. Rising of succeeding crop after harvesting first year crop is known as ratoon crop. Sugar cane is very sensitive to cold injury. During frost conversion of sucrose to glucose takes place. The sugar mill are interested in sucrose while the farmer are interested in sugar cane weight. Therefore we need high sugar and high weight variety. It is a true seeded plant. They have five sub species

· Saccharum spontanium

· Saccharum sinensis

· Saccharum Bari beri

· Saccharum robustum

· Saccharum officinarum

 

SOIL REQUIREMENT:

Sugar cane can be grown in low fertile, medium fertile and high fertile soil. It is very essential the sugar cane should be grown in high fertile soil because of parineal crop and produce high biomass.

CLIMATE:

The sugar cane is tropical crop it can tolerate high temperature but the optimum temperature at the time of sowing should not be less than 12 ºC to 18 ºC. The optimum temperature for growth is 30 ºC.

PLANTING SEASON:

There are two seasons:

· Winter season (September sowing)

· Spring season (February to March sowing)

In winter season intercropping takes place for example onion in Sindh and wheat, mustard in Punjab. In February to March only onion can be sown.

LAND PREPARATION:

Sugar cane requires deep tillage. Deep tillage includes Mould board plough and those farmers who do not have tractor they use Sarkar plough made up of wood. There are two types of sowing in sugar cane. Sugar cane is sow in furrow area as it is water-loving plant. Row to row distance is 3-5 ft.

CONTENTS:

Thin variety seed is sown for 60-70 munds per acre. It contains 13-14% fiber & 70% water, 10-11% sugar and 2-3% impurities, 1-2% glucose. We have to evaporate the water than we will get the sugar. Plant to plant distance is 9-12 inches over lapping of sets take place. Buds and leaf grown alternately. Leaf covers the bud to protect it in order to safe the bud from the outer environments. If the bud damages than the growth does not occurs/ takes place.

SEED SELECTION:

Ratoon type crop are not selected. It is better to cut the top portion of crop as top portion contain good amount of glucose and lower portion contain sucrose. Immature seed is better than mature plant seeds. 40,000 to 60,000 sets are grown in 1 acre.

VARIETIES:

· BL-4 Barbados + Lyallpur

· POJ Java variety in Indonesia

· COL In India 113-116 Comibitor + Lyallpur

· BF Barbados + Faisalabad 129

· BF-162

· Thatta-10

· SPSG-26

· CP Canal point

 

GERMINATION RATE:

· Top portion of sugar cane give 70% germination

· Middle portion of sugar cane give 40% germination

· Basal portion contain more salts therefore its germination is 30%

· Covering of sugar cane is called “rind” which contain parenchyma cells it contain sugar content.

· Roots are known as fibrous roots.

· When the stem bends and than the root which arises are known as butterious roots.

· Basal root contain glucose only which help in growth.

· Earthing up (prevents from water logging) should be done in the month of June.

· One bud can arises 40 to 50 sugar cane.

SEED TREATEMENT:

Sugar cane seed in the form of sets can be treated with fungicides or in hot water.

SOIL FERTILITY:

Before land preparation we need good manuring crop. Before seeding or flowering we have to plough the green manuring. After this we have to irrigate the land in order to decompose the green manuring. Before sowing the crop a month ago we have to do manuring 10 to 15 tones per acre should be use a month ago before sowing the crop. Farmyard manuring should be decomposing properly.

FERTILIZER REQUIREMENT:

First we have to satisfy the phosphorous requirement.

· At sowing:

2 bags of DAP or 2 bags of TSP or 5 bags of SSP and 1 bag of SOP or MOP.

· Seedling stage:

It comes after 1 month of sowing. 1 bag of urea when the temperature is high above 20 ºC than 2 bag of A.N is used.

· Tillering stage:

This stage comes after 2 month of sowing 1 bag of urea. After 3 months of tillering 1 bag of urea is used.

IRRIGATION:

In September sowing (autumn) we need 40%
to 45% time of irrigation of crops. For February to March sowing we need 30% to 34% times irrigation of crop (spring season). For September irrigation we need 4.5-acre foot water. For February to March irrigation we need 3-acre foot of water.

 

DISEASES:

· Red rot

· Whips smut

· Mossaic virus

· Ratoon stunting disease (RSD)

Sugarcane a complete guideCONTROL:

· Healthy seed

· Resistance variety

· Crop rotation

INSECT PEST:

· Termite

· Pyrilla

· Milli bug

· Red mites

BORERS OF SUGAR CANE:

· Stem borer

· Top borer

· Pink borer

· Gurdas pur

Cotton

Cotton means, “thread”. Cotton is an in determinant plant. There are four cultivated species of cotton.

· Gossipium arborium

· Gossipium herbacium

· Gossipium hirsutum

· Gossipium barbaden

All about cottonThe first two species are called Old-world cotton. It is grown in India, Pakistan. Lint is used in textile and stuffing. The last two species Gossipium hirsutum (American Cotton) and Gossipium barbaden (Egyptian Cotton) are grown in Pakistan and known as “Narma”. Main stem of cotton is called Cotton stick. 40 kg of cotton gives 26-27 Kg of Banola seed and 13-14 Kg of lint. Cotton is important cash crop of Pakistan. 60% of export earning is through cotton 85% domestic oil (vegetative oil) is coming from cotton. It provides raw material to 503 mills in Pakistan and 1135 ginning factories. Yield per hectare is more in Punjab than Sindh.

PLANTING REQUIREMENT OF COTTON:

It is warm season crop. The optimum temperature for germination is between 30-35 °C. At the time of flowering temperature is 34-36 °C.

VEGETATIVE GROWTH PATTERN:

Emergence of leaves from nodes takes place. Healthy root system is present for acquiring soil nutrient. Acropetal (Roots) and Basipetal (Leaves) transport system is present. Main stem is called “monopodial” and branches are called “synpodial”. Root growth is 0.5-2.0 inches each day. Cotyledon unfolds at that time root can grow up to 10 cm. At early vegetative stage root is twice than plant height. At the time of boll setting due to demand of carbohydrate root growth become slow. Root activity become slow gradually when plant mature.

IRRIGATION:

Cotton requires moderately to high irrigation. Cotton can not survive in stagnant water.

SOIL REQUIREMENT AND SOIL PH:

Clay loamy soil is best for cotton. Optimum soil pH for cotton is 5.8-6.5 (slightly acidic). Cotton can also be grown in alkaline soil (pH ranges from 8 and above). The soil should be high in organic matter.

VARIETIES:

The main varieties grown in Sindh are

· Kalandri

· M-100

· Cris-9

· Cris-34

· Cris-38

· Sarmast

· Reshmi

· Rehmani

Some Punjab varieties grown in Sindh are

· NIAB-78

· NIAB-98

· Krishma

SEED VARIETY AND GERMINATION RATE:

Seed variety should be 100% pure and germination rate is 75%. 1 lock of boll contains 6-8 seeds.

DELITING:

1 Kg of sulphuric acid = 10 Kg of cottonseeds.

SOIL TEMPERATURE:

At the time of germination soil temperature should be less than 30 ° C. Above 60° C temperatures destroy seedling emergence.

SOWING DATE:

Sowing starts at 15th April. Row to row spacing 2.5-3.0 ft. Plant to plant spacing 9 inches approximately.

SEED RATE:

8-10 Kg seeds per Acre.

SOWING METHOD:

Cottonseed is sown by

· Furrow method

· Ridges method

In flat method 25,000-30,000 plants per acre.

DISEASES:

· Boll rots.

· Nematodes.

· Seedling disease.

· Verticillium wilt.

· Ascochyta blight.