blight

Litchi (litchi chinensis) is a tropical and subtropical fruit tree known for its juicy and aromatic fruits. Diseases in litchi are less. For successful cultivation of litchi, it is necessary to manage the insects that attack it. But for the last few years, Wilt Disease has been seen in litchi which is a vascular disease caused by fusarium oxysporum/solani fungi. This pathogen mainly attacks the root system, disrupts the transport of water and nutrients and makes the tree dry, yellow, and eventually causes death.

Symptoms of Wilt disease in litchi

Although this disease can affect litchi trees of any age, this wilt disease is usually seen more in the new trees of litchi under five years of age, in which the trees would wither away in less than a week. The first symptoms appear as yellow leaves, after that the leaves fall, gradually withering and drying, causing a complete death of the plant within 4-5 days. This fusarium is caused by oxysporum/solani fungus. This requires more research. There is still very few literature available on this disease. Wilt symptoms in litchi are similar to Wilt disease in common. Litchi's Wilt Disease (Wither) is caused by the soft -worn fungus Fusarium oxysporum/solani, which is a terrible threat to litchi orchards worldwide. To maintain litchi cultivation, it is very important to understand the disease, its life cycle and to know management strategies.

Identification and life cycle of fusarium oxysporum

Litchi withering causing agent Fusarium oxysporum/solani, belongs to a group of mild fungi which is known for its wide host border and firmness in the soil. The pathogen infects litchi trees through the roots, occupies the vascular system and causes obstruction of water-rich vessels. As a result, the plants begin to fade and eventually the tree dies. The life cycle of fusarium oxysporum/solani involves surviving as a chlamydospore resistant to the soil. These spores can persist for years, when a sensitive host faces the susceptible root system waiting to be infected, the fungus sprouts and enters the roots, and installs itself in vascular tissues. Then the fungus produces more spore, completes the cycle and maintains the disease.

Factors Contributing to Wilting of Litchi

Many factors contribute to the development and spread of wilting of litchi such as…

Soil Conditions: Fusarium oxysporum thrives in warm and moist soil conditions. Poor drainage and waterlogged soils create an ideal environment for the fungus to infect litchi trees.

Varying susceptibility: Some litchi varieties exhibit resistance to Fusarium oxysporum, others are highly susceptible. The choice of variety significantly affects the susceptibility of the garden to litchi wilt.

Temperature and humidity: Warm temperatures and high humidity favor the growth and spread of Fusarium oxysporum. These climatic conditions provide optimal conditions for pathogens to infect litchi trees.

How to Manage Litchi Wilt Disease?

Management of litchi wilt requires a holistic approach that combines preventive measures, cultural measures, chemical treatments, biological control, sanitation and ongoing research on resistant varieties. Let's take a deeper look at each of these components:

1. Preventive measures

Site Selection: It is important to select well-drained sites to reduce the risk of litchi wilting. Avoiding waterlogged areas helps create a less favorable environment for Fusarium oxysporum.

Selection of resistant varieties: Planting litchi varieties with inherent resistance to the pathogen is a proactive strategy. Ongoing research aims to identify and develop resistant varieties that can withstand Fusarium oxysporum.

2. Cultural (agricultural) measures

Irrigation Management: Proper irrigation practices are essential. It is important to maintain a balance between waterlogging and drought stress to create unfavorable conditions for Fusarium oxysporum. Drip irrigation systems can help deliver water directly to the root zone, reducing soil contact with the pathogen.

Pruning and thinning: Regular pruning of infected branches and thinning of the canopy promote air circulation, reducing moisture around the tree. This, in turn, reduces the chances of fungal spores germination and infection.

Distance between trees: It is very important to have adequate distance between litchi trees. The increased distance facilitates better air circulation, reduces humidity and limits the spread of Fusarium oxysporum.

3. Chemical treatment

Fungicide Application: Fungicides play an important role in the management of wilt of litchi. Fungicides containing active ingredients such as thiophanate-methyl and propiconazole have demonstrated efficacy against Fusarium oxysporum/solani. With preventive treatments implemented during the early stages of disease development, timing of application is important. Treat the soil (active root zone) with a solution of Hexaconazole or Propiconazole @ 2 ml per litre of water or a fungicide called Carbendazim or Roco M @ 2 grams per liter of water and thoroughly soak the soil around the tree. After ten days, thoroughly soak the soil around the tree again with the same solution.

Integrated disease management (IDM): Integrating fungicides with other disease management practices reduces the risk of resistance developing. The IDM approach considers the ecological context and aims for sustainable, long-term disease control.

4. Biological control

Beneficial Microorganisms: Some beneficial microorganisms such as various species of Trichoderma have shown promise in suppressing Fusarium oxysporum/solani. These biocontrol agents can be applied to the soil or used as foliar sprays, providing a natural and environmentally friendly means of disease management.

In litchi, apply Neem cake or castor cake @ 5-8 kg/tree along with recommended dose of fertilizer according to the age of the tree or apply Burmese compost @ 20-25 kg per tree. The use of biocontrol agents such as Trichoderma harzianum, Trichoderma viridi, Pseudomonas fluorescens, etc. has proven effective in the management of the disease. Mix 100-200 grams of commercial formulation of Trichoderma with 20 kg of well-rotted cow dung or compost and spread it per adult tree in the active root zone in a circular strip about 30-40 cm wide on the soil surface at a place where Provide water that is about two feet inside the outer limit of the tree canopy. Ensure adequate moisture in the soil by spraying water or do light irrigation

Microbial consortia: Research is ongoing to develop microbial consortia that utilize the synergistic effects of multiple beneficial microorganisms. These consortia offer advanced disease suppression while reducing environmental impact.

5. Cleanliness

Debris Removal: It is important to promptly remove and destroy infected plant debris to eliminate potential sources of inoculum. Fallen leaves, cut branches and other plant material should be disposed of properly to prevent the persistence of Fusarium oxysporum in the garden.

Tool Disinfection: Regular disinfection of pruning tools and equipment helps prevent the inadvertent spread of fungus between trees. Hygiene is essential to reduce the risk of disease transmission during garden maintenance.

6. Research on resistant varieties

Breeding Programme: Continuous efforts in breeding programs are aimed at developing litchi varieties with inherent resistance to Fusarium oxysporum. Identifying and promoting resistant varieties is a sustainable long-term solution to litchi wilt.

Genetic Engineering: Advances in genetic engineering can accelerate the development of resistant varieties. By introducing genes that confer resistance to Fusarium oxysporum, researchers aim to increase litchi's ability to withstand the pathogen.

7. Precision Agriculture Technology

Remote sensing: Precision agriculture technologies, including remote sensing, enable growers to monitor orchard health from a distance. Drones equipped with sensors can detect early signs of disease, allowing targeted intervention and timely disease management.

Data Analytics: Analysis of data collected through precision agriculture technologies provides valuable insights into disease dynamics. This information guides growers in optimizing management practices and improving overall orchard health.

Summary

Litchi Wilt (Wither) management requires multidimensional and integrated approaches. From preventive measures and cultural measures to chemical remedies, biological control, hygiene and ongoing research on resistant varieties, each component plays an important role in reducing the impact of fusarium oxysporum. It is necessary to ensure the livelihood of producers facing a holistic strategy, maintaining litchi orchards, and through the challenges of lychee withering.

Bacterial leaf blight disease is a major threat to rice production worldwide, as rice is the staple food of more than half of the global population.

Following are the symptoms, causes, epidemiology, various management measures of Bacterial Leaf Blight (BLB)

Introduction

Bacterial leaf blight in rice produced by Xanthomonas oryzae pv.oryzae .This disease is one of the most damaging ones  to paddy plants. Bacterial leaf blight (BLB) predominantly affects the leaves of rice plants and can cause severe output losses if not carefully handled.

Also  read: Steps towards a vaccine to reduce rice yield losses due to diseases

Symptoms of BLB

BLB symptoms usually start as tiny, water-soaked lesions on the leaves and progress to elongated, yellow to brown stripes. These stripes are generally wavy and run the length of the leaf blade. As the illness advances, tiny spots combine, causing entire leaves to perish. In extreme circumstances, BLB also damages leaf sheaths and panicles, resulting in significant yield losses.

Causes and pathogens

BLB is caused by the Gram-negative bacteria Xanthomonas oryzae pv oryzae, which lives in the intercellular spaces of rice plants. It penetrates the plant via wounds or natural pores and multiplies inside the plant tissues, resulting in disease symptoms. The causative agent of this illness produces a number of virulence factors, including extracellular enzymes and toxins, which contribute to its pathogenicity.

Epidemiology

BLB thrives in warm, humid settings, making it most common in tropical and subtropical locations. Raindrops, wind-blown rain, irrigation water, polluted agricultural equipment, and plant debris all contribute to the disease's spread. The presence of the infection in seeds also causes the spread of BLB to new locations.

Also read: Know about major diseases in paddy crop and how to control them

Disease cycle

Understanding the disease cycle is critical for effectively managing BLB. It starts with the pathogen being introduced into a paddy field and then spreads to host plants. Infected plants discharge bacterial cells into the environment, infecting adjacent plants. Environmental elements including temperature and humidity impact the disease's progression.

Impact of BLB on paddy production

BLB leads to considerable economic losses in paddy production. Yield losses in highly damaged areas might vary between 20% and 50%. These losses have an impact not just on food security, but also on rice farmers' livelihoods, particularly in places where paddy is the predominant staple crop.

How to control BLB?

Let's talk about the solutions

Use of resistant varieties: Breeding programmes have produced rice cultivars with varied levels of resistance to BLB. These resistant types can significantly lower the severity of the illness.

Crop rotation:which includes non-host crops, helps to prevent pathogen buildup in the soil.

Hygiene: Proper sanitation practices, such as eliminating contaminated plant debris and sanitising agricultural implements, help to prevent the infection from spreading.

Chemical control: Copper-based bactericides and antibiotics can be used in conjunction to reduce BLB, although their efficacy may decline over time owing to resistance. To treat this illness, spray 2.5 grammes of copper oxychloride per litre of water and 0.5 grammes of streptomycin per litre. From a distance, the signs of this condition appear to be zinc insufficiency. If zinc (Zn) deficient symptoms are present, spray the paddy with a mixture of 5 grams of zinc sulphate and 2.5 grams of slaked lime per litre of water. Zinc insufficiency is readily handled.

Biological control: Beneficial bacteria and biocides are being investigated as environmentally beneficial alternatives to BLB management.

Also  read: You can reduce your agricultural costs by adopting organic pest control tips.

Challenges and possible future

Despite efforts to manage BLB, issues persist. The introduction of new disease strains with higher virulence has the potential to overcome previously resistant kinds. Furthermore, there is a need to establish sustainable and eco-friendly management approaches to lessen the environmental effect of chemical control techniques.

To summarise, bacterial leaf blight of rice is a devastating disease that has a significant impact on rice production and food security in many regions of the world. Understanding its origins, symptoms, and management measures is critical to mitigating its impact and ensuring a steady supply of rice for the world's rising population. Continued study and collaboration among scientists, farmers, and policymakers is critical in the ongoing fight against BLB.

Pusa agricultural scientists have put an advisory for the farming of wheat in rabi season. In which they pointed out that those farmers with 21-25 days wheat crops should go with first irrigation within the upcoming 5 days.  After 3-4 days of irrigation, second fertilisers should be put in. According to agricultural scientists, considering the temperature, farmers are advised to sow the late wheat crops as soon as possible. Sowing rates to be kept 125 kilograms of seeds per hectare. It's advanced species are HD 3059, HD 3237, HD 3271, HD 3369, HD 3117, WR 544 and PBW 373.

Must do seed treatment 

Before sowing seeds should be treated with bavistin @1.0 gram or thiram @2.0 gram per hectare. For your knowledge, in farms infected with termites, chlorpyrifos (20 ec) @5.0 litres per hectare should be spread with paleva or in dry farms. The amount of nitrogen, phosphorus and potash fertilisers to be kept is 80, 40 and 40 kilograms per hectare. 

Rarefaction of mustard crops must be done on priority.

Weed control and rarefaction should be done in lately sown mustard crops. Considering fall in average temperature, mustard crops should specially be taken care of for white rust disease. Rotten/fermented dung and potash fertilisers must be used before sowing onion crops in prepared farms in this season. Potatoes and tomatoes are more prone to blight disease because of heavy moisture in the air. That's why, look carefully for crops. In case of symptoms, spray 2gram dithane-M-45 in per litre of Water. 

Farmers should check regularly for leaf feeding insects 

For your interest, farmers who have prepared a nursery of tomato, cabbage, cauliflower and broccoli. They can show their plants considering the weather. Cauliflower and cabbage family plants should specially be taken care of leaf feeding insects. If they are in large numbers, then spray BT @1 gram per litre of water or sponosade medicine @1.0 ml per 3 litres of water. In this weather, farmers must get rid of weeds with the help of weeding-hoeing practice. Vegetable crops should be irrigated and then fertilisers should be put in.

How farmers should manage stubble remains 

Farmers are advised not to burn the remains (stubble) of kharif crops(paddy). This results in polluting the environment too much. The smog produced by this does not allow complete sunlight to reach crops and farms. It affects the photosynthesis and evaporation in plants which leads to low food production in plants. It also affects the amount of produce and quality of produce. Farmers are advised to mix or dig the remaining paddy stubble in soil, it increases the fertility of soil.

There is an infection of the nematode inside the pomegranate, a tiny microscopic and thread-like round organism. It forms knots in the roots of pomegranate. Due to its effect, the color of the leaves of the plants starts turning yellow.

Pomegranate cultivation proves to be a very profitable deal for the farmers. The pomegranate plant is quite tolerant and can tolerate all types of weather. Pomegranate plants and fruits suffer huge losses due to insect and disease infestation. Therefore, farmers must have the necessary information related to the control and identification of diseases and pests in pomegranate cultivation. What kinds of diseases and pests affect pomegranate plants and fruits? What are the symptoms to identify it? Also, it is very important to know what measures should be taken to prevent it. 

The following pests affect the pomegranate crop: 

There is a lot of infestation of nematode in pomegranate, which is a microscopic microscopic and thread-like round organism. It forms nodes in the roots of pomegranate. Due to its attack, the leaves of the plants also start turning yellow and curling. Due to this, the growth of plants stops. Along with this, production also gets affected. For this reason, dig near the roots of the plant that is showing signs of infestation by this pest, add 50 grams of phorate 10 g to it, mix it well with the soil, and irrigate it. With this, the plants can be protected from damage. Apart from this, there is an infestation of insects like mealybug, moila thrips, etc. Due to this, buds, flowers, and small fruits start spoiling and falling in the initial stage itself. To prevent this, mix 0.5 percent solution of dimethoate insecticide in every liter of water and spray it on the crop.  

Also read: Which state produces maximum pomegranate in India?

Take the following measures for protection from mites 

Mite infection can also occur in plants. These are very small creatures, which are usually found in white and red colors. These small creatures suck the juice by sticking near the veins on the upper and lower surface of pomegranate leaves. Mite-infested leaves turn upwards. Apart from this, when the infestation of this insect is severe, all the leaves fall from the plant and it dries up. Therefore, when symptoms of mite infection are seen in pomegranate plants, spray 0.1 percent solution of Exide medicine on the plants. Do this spraying at an interval of 15 days. 

Butterfly moth is very harmful to pomegranate

Butterflies are considered to be the most harmful insect for pomegranate fruits. Because when an adult butterfly lays an egg, the caterpillar emerges from it and enters the fruit. After entering the fruit, it eats the pulp of the fruit. To control it, spraying 0.2 percent deltamethrin or 0.03 percent fucoidan insecticide solution during fruit development during the rainy season is very beneficial. It should be sprayed at an interval of 15-20 days.