Pests, viral diseases threaten standing kharif crops, push up chemicals use

An increase in monsoon activity and resultant humidity has seen a significant proliferation of pests and viruses across states and crops, leading to greater application of chemicals

With most parts of India except some regions of east and north-east India receiving above-normal rains this monsoon season, standing crops across several areas are seeing increased attacks of pests and diseases, a direct fallout of humid weather.

 

This, in turn, has meant that farmers' expenses on sprays and pesticides have gone up considerably this kharif season. Worryingly, unless the higher use is controlled properly, it could have an impact on the final yields.

 

Overall, the area under kharif crops as of the first week of August this year was almost 5 per cent more than last year, with paddy, maize, and moong leading the way. Among the laggards are cotton, urad, arhar, soybean, and groundnut.

 

In the case of cotton, though, industry associations feel that despite lower acreage compared to last year, overall production would be better than the 29.4 million bales of 2024—25 season that ends in September. However, that does not mean that this year's crop has been devoid of trouble.

 

Multiple states, crops see pest attacks

 

A recent field survey by the Jodhpur-based South Asia Biotechnology Centre (SABC) under ‘Project Bandhan’ found an alarming infestation of green leafhoppers (jassid), commonly known as ‘hara tela’ on cotton across major cotton-growing districts of Haryana (Hisar, Fatehabad, Sirsa), Punjab (Mansa, Bathinda, Abohar, Fazilka), and Rajasthan (Hanumangarh, Sri Ganganagar).

 

A field team of SABC scientists led by Dr Dilip Monga found infestation levels of 12-15 leafhoppers per leaf, significantly above the Economic Threshold Level (ETL).

 

Notably, the field survey not only reported alarming numbers of leafhopper per leaf but also cotton leaf injuries exceeding ETL based on damage grading system.

 

“For the past three consecutive weeks, green leafhopper (jassid) populations have exceeded ETL, triggering widespread yellowing of leaf margins and downward curling, classic symptoms of jassid attack,” the survey report said in its findings at the end of July.

 

The outbreak is being attributed to a confluence of weather conditions, including above-average rainfall, an increased number of rainy days, persistent humidity, and cloud cover, all of which have created ideal conditions for jassid proliferation.

 

Experts confirm this is the worst outbreak in a decade in north India's cotton growing zone.

 

“The leafhopper infestation has emerged at a time when the cotton crop stands, and overall conditions are significantly better than the past three-four years. The crop appears robust across the northern region, except in late-sown areas of Sri Ganganagar, where irrigation was unavailable during the sowing period”, said Dr Bhagirath Choudhary, founder and director of SABC.

 

What is the leafhopper pest?

 

Leafhopper or Amrasca biguttula biguttula (Ishida) is commonly referred to as an Indian cotton jassid or ‘hara tela’ and is a season-long sucking pest of cotton.

 

Leafhopper adults are very active, pale green in colour measuring about 3.5mm in length, with two distinct black spots on forewings and vertex, and can be readily identified by their characteristic diagonal movement on the leaves, which has earned them the leafhopper moniker.

 

Population of leafhoppers occurs throughout the season but attains pest status during July-August. Up to 11 generations per season have been estimated to occur on cotton.

 

Both nymphs and adults of leafhoppers suck the cell sap from the cotton tissue and inject a toxin causing ‘hopper burn’ symptoms, characterized by yellowing, browning, and drying of leaves.

 

The affected leaves show crinkling and curling symptoms and in extreme situations result in reduced photosynthetic activity. They also cause browning and drying of leaves that can considerably hamper the productivity of the cotton, and yield losses of up to 30 per cent if unmanaged. Leafhopper also affects brinjal, cacao, pepper, potato, and other crops.

 

Fiji virus hits Haryana

 

Apart from leafhopper disease in cotton, the standing paddy crop in Haryana has been infected by the Fiji virus this year.

 

This virus, which causes dwarfing in paddy plants, was seen in the fields of Karnal, Kurukshetra, Ambala, Kaithal and Yamuna Nagar.

 

The diseases threatened to severely impact paddy yields, prompting farmers to demand special 'giradwari' (crop survey) of all paddy fields across the state for correct assessment of the impact of the virus on the fields and its mitigation efforts.

 

Some reports said the virus could reduce yields by almost 80 per cent unless treated properly.

 

“Farmers should immediately get a special one-time compensation of at least Rs 50,000 acre to mitigate the losses suffered due to the virus,” said Inderjit Singh Goraya, national spokesperson of the All India Kisan Congress and a Haryana Pradesh Congress Committee member.

 

The state government is reported to have ordered a special assessment drive to judge the extent of the Fiji virus and is taking measures to minimise its impact.

 

Pest attacks in other crops

 

Apart from cotton and paddy, farmers in many other parts of the country have also reported increased incidents of pest attacks this year.

 

The tomato and chilli crop has been infected by ‘black thrips’ while the groundnut crop in some parts of Gujarat has been hit by ‘white grub’ disease for some years now.

 

In mung beans, parts of the standing crop have been impacted by deadly ‘helicoverpa’ pests this year. In pearl millet, a local pest called ‘katra’ beetles or red hairy caterpillars has infested several fields.

 

“With climate change becoming an everlasting phenomenon in agriculture, the threat of sucking pests attacking standing crops and viral diseases impacting yields has grown manifold as pests and diseases thrive on high humidity and muggy weather,” Choudhary said.

 

Monsoon plays spoilsport

 

The southwest monsoon has been unusually heavy this year with central, western and north-western parts of the country receiving more than normal rains till August 18.

 

Data from the India Meteorological Department (IMD) shows that between June 1 and August 18, the southwest monsoon has been 13 per cent above normal in north-west India, 4 per cent excess in central India, 6 per cent surplus in south peninsular India and only 18 per cent below normal in east and north-east India.

 

Cumulatively, the all-India average monsoon rainfall across the country so far this year has been around 600 millimetres (mm) as against the normal of 596 mm. This means that it is just one percent above normal. The moisture and humidity levels have been above on the higher side for some time now.