Whiteflies are small, sap-sucking insects commonly found on the underside of leaves. They belong to the family Aleyrodidae and are a major pest of many crops, including Green Gram. Whiteflies can cause significant damage to plants by feeding on the sap, leading to stunted growth, reduced yield, and transmission of viral diseases.
There are several species of whiteflies, but the most common ones found in Green Gram are the Bemisia tabaci and Trialeurodes vaporariorum. Both species are polyphagous, meaning they can feed on various plants, including weeds and ornamentals. Managing whiteflies in Green Gram requires a combination of cultural, biological, and chemical control methods.
Cultural practices such as crop rotation, planting resistant varieties, and proper sanitation can help reduce whitefly populations. Biological control agents like parasitic wasps and predators like lady beetles and lacewings can also control whiteflies. Chemical control should be used as the last option. To avoid damaging non-target insects and the environment, apply insecticides at the recommended rates and schedule.
Whitefly Management in Green Gram
Identification of Whitefly
Whiteflies are small insects; their body and each pair of wings are covered with a white to yellowish powder, waxy secretion. They measure between 0.8 and 1 mm and have a distinct appearance. Whitefly eggs are deposited on the underside of the leaves, where they hatch into yellow to white, flat, oval, and pale green-colored nymphs. Adult whiteflies cannot survive for a few days without feeding on a host plant. Commonly found on the underside of the leaves, they will form a cloud if disturbed.
The Life Cycle of Whitefly
The life cycle of a whitefly can be divided into four stages: egg, nymph, pupa, and adult. The eggs of whiteflies are tiny, measuring only 0.2 mm in length. They are laid on the underside of leaves, where they hatch into first instar nymphs that are only 0.3 mm in size. The nymphs go through two to three instars, increasing in size to 0.4-0.6 mm.
They then develop into fourth instar or red eye pupae that are 0.6-0.8 mm long. Finally, the adults emerge, minute insects with yellow-colored bodies covered in white waxy bloom. The entire life cycle takes around 18 to 28 days in warm weather.
Causes/Conditions Favorable for Whitefly Spread in the Field
Whiteflies can multiply and spread quickly when the temperature is high, the humidity is low, and the air is dry. Overcrowding of plants, lack of proper sanitation practices, and the presence of weeds can also contribute to the rapid spread of whiteflies in the field
Damage Symptoms of Whitefly
Whiteflies cause major damage to plants by feeding on their sap. Both the nymphs and adults of whiteflies can be found in large numbers on plants, and their feeding can result in yellowing and mottling of leaves, stunted growth, and premature defoliation. Severe infestations can lead to the shedding of flowers and pods and the development of sooty mold or honeydew on the leaves. Whiteflies are known to spread plant viruses, like the yellow mosaic virus, and the damage they do when they eat.