Deforestation, chemicals blamed for pest attack on paddy
Source: The Sangai Express

Imphal, September 03 2020: The recent attack on paddy cultivations across Manipur valley by Brown Planthopper (Marek Angangbi) and White Blacked Planthopper (Waikup Manbi) have been attributed to rampant deforestation and indiscriminate use of fertilizers.

CAU Imphal Entomologist Dr Kh Ibohal said that extensive damage was done to paddy cultivation (first crop) by Brown Planthopper and White Blacked Planthopper some 7/8 years back but they did little damage during the main cropping season.

Yet, since the past 5/6 years, Brown Planthopper and White Blacked Planthopper are becoming the most common pests which attack paddy cultivations in Manipur as a result of rampant deforestation and indiscriminate use of chemicals/fertilizers, Dr Ibohal said.

Rampant deforestation and indiscriminate use of chemicals/fertilizers have created a very favourable environment for massive reproduction of the two pests, he said.

Failure to treat paddy seeds with appropriate chemicals or spray pesticides when the two pests start attacking paddy plants also abet massive invasion on paddy plants by Brown Planthopper and White Blacked Planthopper, said the Entomologist.

Using same type of pesticides for successive years, spraying of pesticides which do not have the required doses of its components and use of Urea help in recurrence of Brown Planthopper and White Blacked Planthopper, he continued.

Brown Planthopper and White Blacked Planthopper usually attack plants together and they thrive well in water.

While Brown Planthopper lays 200 to 250 eggs in a lifetime, White Blacked Planthopper lays 130 to 150 eggs in a lifetime.

They attack paddy plants starting from transplanting stage till the plants are fully matured.

If the plants are excessively infected by Brown Planthopper and White Blacked Planthopper, reddish patches as large as banana leaf can be seen in paddy fields.

Sometime, one may see paddy plants dying and dried as if they have been burned, Dr Ibohal said.

Infection of paddy plants by root aphid (wahik) was detected recently in some paddy fields of Sabungkhok, Imphal East district which have relatively lower level of water in addition to Brown Planthopper and White Blacked Planthopper, he continued.

On account of the COVID-19 lockdown, farmers could not move around freely to procure necessary inputs like chemicals, pesticides etc and they really struggled hard to cultivate paddy this season, he remarked.

It is a matter of grave concern that Brown Planthopper and White Blacked Planthopper have been attacking paddy plants when the plants are maturing.

On protection of paddy plants from the two pests, Dr Ibohal suggested replacement of Urea with Potash for some time.

Even though it is not the season, the two pests can be killed if farmers can scatter pieces of pomelo peels in the paddy fields.

Even if pomelo peels are not available at the moment, peels of other fruits belonging to the same family as pomelo would be effective enough, he said.

Farmers may also dissipate cow dung solution if wet cow dungs are available.

Cow dung solution should be dissipated until the water of paddy fields becomes the colour of cow dung, Dr Ibohal suggested.

In addition, appropriate pesticides may be used in accurate doses to kill the two pests but the present stage of infection cannot be controlled by any pesticide.

However, if the same pesticide is used repeatedly for consecutive years, Brown Planthopper and White Blacked Planthopper would adapt to the new environment and their numbers would only multiply, warned the Entomologist.

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