Manipulation of intercropping technology for conservation of predaceous ladybird beetles (Coleoptera: Coccinellidae) to aphids (Hemiptera: Aphididae) management

Experiments were made on the feasibility of canola-based maize intercropping to observe population and conservation of aphidophagous ladybird beetles and their ultimate impacts on aphid’s density and crop yield. Experimental treatments were, canola 4 rows+ maize single row, canola 4 rows+ maize double row intercropping, and their comparison with canola and maize grown alone to generate data whether these combinations had encouraging or discouraging influences on useful and harmful insect populations. The striking result of this study was impacts of maize intercropping to enhance predators and suppress the pests populations. Data on populations of aphid and maize borer had shown significantly more numbers of pests noted in treatment of canola and maize, respectively, planted alone compared to canola intercropped with double rows of maize. Double lines of maize plus canola intercropping gave better results than single line for holding higher predator populations. Results achieved indicated that canola and double row maize intercropping generated better conservation of coccinellid beetles for aphid or borer control than single row maize and check treatment, and yielded higher produce. This could be attributed due to the capacity of double row maize planting to hold maximum numbers of ladybird beetles and their more severe competition to predate upon the pests prey. And owing to low level of pest populations on intercropped canola and maize plantings, these produced significantly higher seed yields. The predominant emerging observation was that the intercropped maize exhibited proficient shelter and roosting sites for coccinellids during peak winter season, which was a remedy against hibernation and dispersion constraints upon these predators. Based on the outcomes made during current experiment, the implications of existing knowledge and prospects would facilitate implementation of intercropping strategy to enhance suppression of insect pests.