INSECTICIDE USE PATTERNS AND RESIDUE LEVELS ON CABBAGE, Brassica olerecea var. capitata L., CULTIVATED WITHIN THE ACCRA-TEMA METROPOLITAN AREA OF GHANA

ABSTRACT

Concerns have been expressed by pesticide management specialists about the choice and use of

insecticides in cabbage production and fear o f toxic residues on harvested cabbage head. This

investigation involves a survey to determine cabbage fanners’ insecticide use patterns and analysis

for insecticide residues on samples o f cabbage.

The survey revealed that cabbage growers in the Accra-Tema Metropolitan area o f Ghana

invariably relied on insecticide retailers/agents for advice on the choice and use o f insecticides for

insect pest control purposes. The insecticides o f choice were, Bacillus thuringiensis subsp.

kurstaki Berliner, Lambdacyhalothrin, Chlorpyrifos, Dimethoate, Deltametrin, Triazophos,

Cypermethrin, Profenofos and Pirimiphos-methyl. These insecticides were used either in

alternation or as mixtures. Additionally, the insecticides were sprayed frequently and at short

intervals on cabbage without the consideration o f threshold levels.

Residues of Karate 2.5 EC (Lambdacyhalothrin) and Deltaphos 262 EC (250g/l Triazophos +

12g/l Deltamethrin) were determined on samples o f cabbage, by estimation o f biotoxicity to the

brine shrimp nauplii. Residues o f Lambdacyhalothrin were lower than the FAO/WHO

recommended maximum residue level (MRL). The residues o f Deltaphos 262 EC detected,

however, suggested that the residue levels o f Triazophos were likely to be higher than FAO/WHO

recommended MRL