Assessment on the Effects of Intercropping Patterns on Incidence and Damage to Cotton by Diaparopsis Castanea: Hampson (Lepidoptera: Noctuidae) in Magoye, Mazabuka District of Zambia

Abstract

The Red bollworm, Diaparopsis castanea (Hampson) is an insect that has gone from being a minor cotton pest to being a major pest of cotton in Zambia. This study was conducted in Magoye, Mazabuka district, Zambia to assess the effects of intercropping patterns on the incidence and damage caused to cotton by D. castanea. The first part of the study involved conducting a survey among 80 randomly selected farmers in Magoye to determine the different types of intercropping patterns being used in the area. The second part of the study was an experimental field study to assess various intercropping patterns identified in the survey. The experiment was laid out in a randomized block design with four replications. Cotton cultivar CDT II (Gossypium hirsutum) was sown by hand in 100-cm spaced single rows. The intercrops selected were maize (Zea mays L.), sorghum (Sorghum vulgare L.) pigeon pea (Cajanus cajan L.), cowpea (Vigna unguiculata L.) and sunflower (Helianthus annus L.). The data collected was subjected to analysis of variance (ANOVA) technique and LSD using GenStat discovery edition 3 computer package. The survey revealed that only 28% of farmers in Magoye area were using intercropping as a pest control strategy. The intercrops were grown either as a strip/single row pattern alongside the cotton crop or in between each row of cotton. Analysis of variance (ANOVA) on the field study showed significant differences (F =2.22; d.f =5; p<0.001) in incidence of D. castanea egg, average damage to cotton bolls (F = 1.25; d.f = 5; p<0.001) and average seed cotton yield (F =1.17; d.f = 1.17; p<0.001) across the various intercropping patterns.