MULTAN, Aug 25: Cotton cultivators must avoid over-irrigation of the crop that is satisfactorily bearing fruit these days, advises Central Cotton Research Institute Director Muhammad Islam Gill.

Talking to this agency on Wednesday, he stressed that the crop should be watered according to its need. "Apply only that much water that can be absorbed by the soil within 36 hours. Flowers at the top of the plant indicate water stress, which must be avoided," he added.

The CCRI director, who is also a researcher, said application of nitrogen fertilizer should be completed in time, as any delay would hamper crop maturity and attract late season pests.

He said in case of rain if water was expected to stay for over 36 hours in the field, it must be drained out. Answering a question, he observed that the current weather was good as well as bad for the crop. "The growers must remain extra careful," he said.

Mr Gill emphasized the need to inspect fields twice a week to assess the magnitude of the pest problem. In case of a pest attack above the economic threshold level, right dosage of pesticides should be used to protect the crop.

He said the economic threshold levels for various pests was: jassid - one adult or nymph per leaf; white fly - five adultsor nymphs per leaf; thrips - eight to 10 adults or nymphs per leaf; spotted bollworm - three larvae per 25 plants; pink boll worms - five larvae per 100 bolls; helicoverpa - five brown eggs or three small larvae or collectively five per 25 plants, and army worm - localized treatment where found.

The crop must be inspected after 72 hours of the spray and immediately after a rainfall to assess the efficiency of the application. The CCRI chief stressed the need to ensure selection of the right pesticide, dosage and application, as these were key factors in crop protection.

He also urged farmers to spray the crop in the morning or late afternoon for the best results. He advised that the flow rate from the nozzle must beuniform and should be in fine mist. -APP