The efficacy of alternative (biorational) insecticides in suppressing damage caused by insect pests affecting callaloo, Amaranth xanthosoma andpak choy, Brassica rapa, production in Jamaica

Abstract

Changes in climate are likely to result in more frequent and intense pest outbreaks and with the pervasive use of broad spectrum synthetic insecticides within agricultural production systems in Jamaica, this is likely to lead to the increased use of synthetic pesticides, which are known to have adverse environmental effects and increase the risk of unacceptable levels of residue entering the food chain. Monitoring by the Pesticide Control Authority of Jamaica revealed more frequent detection of synthetic pesticide residues on pak choy and callaloo, thus highlighting the need to identify less hazardous pesticides for use on these crops. This study aimed to assess the efficacy of selected biopesticides against insect pests affecting callaloo andpak choy production in the parishes of Clarendon, St Elizabeth and Kingston. Monitoring began a week after plots were established to assess pest damage and treatments done when damage reached a pre-determined economic threshold. Yield was assessed at the end of the crop cycle. The percentage damaged leaves varied significantly (P=0.012) by type and location of crop ranging from 35.49 ±2.53 % in Kingston to 69.89±2.71 % in St. Catherine. However, there was no significant difference in the harvested yield (315.2±11.8–475.7±33.0 grams/plant). There was also no significant difference in the marketable yield from plots treated with biorationals (211.2±31.3g – 288.1±16.1 grams/plant) when compared to plots treated with synthetic pesticides (188.5±13.3g–216.6±26.5 grams/plant).