Abstract
Cotton is an invaluable crop to many countries in the world. It provides raw materials in the textile industry. It is also important to oil expressers and livestock feed makers. In Zimbabwe it is a source of foreign currency to the state and income to many. Many factors, which include susceptibility to attack by sucking and chewing insect pests, has led to low productivity of cotton. Jassid, a sucking pest, is a major threat to cotton. Jassid infestation leads to significantly lower amounts of yield with a degraded quality of fibre, creating problems when processing lint. An experiment to evaluate the efficacy of Azadirachtin 0.1% EC, a biopesticide against jassid in cotton, was conducted at Cotton Research Institute (CRI) in Kadoma, for two seasons (2022/23 and 2023/24) in Zimbabwe. The trial was laid out in a Randomized Complete Block Design (RCBD) with six treatments, which included a no control, four doses of Azadirachtin 0.1% EC at 300ml/ha, 500ml/ha, 750ml/ha, and 1125ml/ha, Dimethoate 40EC at 250ml/ha (control). The gross plot was 6 rows x 8m = 48m2 and the sampling area was 4 rows x 6m = 24m2. Measurements were jassid counts, jassid damage, and predator counts. Data not normally distributed was transformed using the square root of (x+3/8). Data analysis was done using GenStat 14th Edition. Test chemical Azadirachtin 0.1% EC (P<0.005) showed a comparable performance with the standard treatment Dimethoate 40EC on jassid control at all rates. All rates of Azadirachtin were statistically similar to the standard check (P<0.005). The control treatment had statistically higher jassid populations (24.94) than all the Azadirachtin rates. Azadirachtin 0.1% EC was recommended for registration for control of cotton jassids in Zimbabwe at a rate of 500ml/ha.