Effect of Weed Management on Insect Pest Population on Cotton (Gossypium Hirsutum L.) At Werer, Ethiopia

Abstract

Weeds are important hosts of insect pests and pathogens in agroecosystems. Van Emden and Dabrowski (1997) cites 442 references relating to weeds as reservoirs of pests. More than seventy families of arthropods affecting crops were reported as being primarily weeds associated (Bendixen and Horn, 1981). Many pest outbreaks can be traced to locally abundant weeds belonging to the same family as the affected crop plants. Many insect pests are sufficiently polyphagous and thus, weeds unrelated to the crop may also be pest reservoirs. For example, Aphis gossypii feeds on over twenty unrelated weed species within and around cotton fields. Weedy plants near crop fields can provide requisites for pest outbreaks. Gliessman (2001) reported that weed borders are used in an agroecosystem to attract insects, facilitating colonization in the adjacent cauliflower crop.