About Thrips

Thrips are small insects (Fig.) that live in the flowers and folded leaflets of groundnut. They are pale cream in color, and are usually hidden. For these reasons they are not conspicuous. They can be present at any time of the year but are most numerous in the post-rainy season.

 

 

 

 

Enlarged Picture of a Thrip

Crop Damage

 

 

 

 

 

 

 

 

 

 

 

                    Yield reduction                         Bud necrosis affected plant on the right

                     is not serious                                  and resistant one on the left 

Nymphs and adults suck sap from the surface of the leaflets initially resulting in white patches on the upper and necrotic patches on the lower surface of the leaves. In severe infestations, particularly in the winter crop (November-sown in southern India), leaf distortion causes stunted plants. Thrips are more dangerous to the crop as they transmit peanut bud necrosis virus disease, which can cause widespread plant death (Fig.).

Management

Farmers often apply insecticides to control thrips. This often results in outbreaks of more serious pests. Insecticide application does not help to reduce levels of bud necrosis disease. Grow varieties resistance to thrips like Robut 33-1, Kadiri 3, and ICGS 86031 in endemic areas to reduce the risk of thrips damage and bud necrosis disease. If there are more than five thrips per terminal (folded) leaf during 30 days after emergence in the post rainy season, apply Dimethoate at 200-250 ml a.i./ ha. Thereafter, it is not necessary to use insecticides for thrips control.