AFRICAN MARIGOLD AS A TRAP CROP FOR THE MANAGEMENT OF THE FRUIT BORER HELICOVERPA-ARMIGERA ON TOMATO

The possibility of using okra, field bean, pigeon pea, sunflower, maize and marigold as trap crops for the management of the fruit borer Helicoverpa armigera (Hubner) on tomato was evaluated. Initial experiments involved observational row trials with simultaneous planting/seeding of both tomato and trap crops in exploded blocks. One row of these crops was raised on either side and parallel to 10 and 15 rows of tomato respectively. Results indicated that use of African tall variety of marigold cv. Golden Age afforded maximum reduction of both eggs and larvae of H. armigera in the intercropped tomato with a consequent reduction in the number of bored fruits. The rest of the crops were ineffective because they were less preferred and also because flowering in these crops did not synchronize with tomato. Based on the success in observational row trials, systematic studies involving planting combinations of 10, 12, 14, 16, 18 and 20 rows of tomato were evaluated with one row of marigold planted on either side and parallel to each of these combinations. Intercropped tomato was not sprayed until harvest. The percent of fruits damaged in 10, 12, 14, 16, 18 and 20 intercropped rows of tomato were 6.0, 7.1, 10.3, 10.4, 14.1 and 14.5 respectively. Control plots recorded 56.1% fruit borer damage. Later studies involved evaluation of one row of marigold raised on either side and parallel to 14 and 16-rows of tomato. During this experiment, two sprays with 0.07% endosulfan were superimposed on the intercropped tomato and less than 6% fruit borer damage was recorded.