Cabbage Integrated Pest Management : An Ecological Guide.

Major Cabbage Insect PestsTrap cropping for DBM control in IndiaIn India trap crops are being used in IPMFarmer Field Schools. The trap crop used wasmustard. The recommendation of the IndianFFS is to sow two rows of mustard after every9 rows of cabbage. The first row of mustardshould be sown 15 days before the cabbageis transplanted and the second row of mustardabout 15-25 days after transplanting thecabbage. Diamondback moth prefers mustardto cabbage. The trap crop was also an effectivetrap for other caterpillars and aphids (Srinivasan, 1991). Whether or not the mustard needs to sprayedor destroyed to remove the pest insects, is disputable. This can be tested in a study.· Sometimes, planting a trap crop around the field helps to control DBM. The trap crop, whichshould be established before the cabbages are transplanted, will attract pest insects. These pestinsects in addition, will attract natural enemies. The trap crop is either destroyed together with theDBM larvae or left in the field as a “natural enemy reservoir”. See box above and section 3.10.2.These trap crop plants should be monitored with more frequency than the main crop and requirecontrol of the DBM before it can be passed to the main crop. Unattended trap crops can generatelarge populations of DBM! Special care is needed to manage these crops to use them as part ofa control practice.In fact, several researchers report that combining trap crops with release of parasitoids is a verygood DBM management practice. See example in box below.Combining trap crops with release of parasitoidsFor highland areas the Indian Institute of Horticultural Research (IIHR) advises to grow the boldseededIndian mustard as a trap crop. This attracts up to 80% of DBM, and should be sown thicklyall around the area where crucifers are to be grown, at least 10 days before the cruciferous cropsthemselves. Releasing the parasitoid Diadegma semiclausum on the 16th and 21st days after planting.The recommended number of parasitoids to release is 3,000 pupae per hectare per release date in acrop cycle of 70 - 80 days. Spraying with 4% neem seed kernel extract (NSKE) once every threeweeks, if necessary, to help control aphids. NSKE can be sprayed onto the mustard to control DBMand aphids. Not more than 3 NSKE sprays are required (ref. www22).For lowland areas, the following research results were good:Planting collards as a trap crop in and around cabbage fields lured a significant number of DBMadults away from the cabbage. Supplemental releases of Cotesia plutellae in the collard plantingswould allow this parasite to build its numbers along with Diadegma insulare, and both species couldspread into the cabbage to attack DBM larvae. This approach could greatly reduce grower costs asfewer C. plutellae parasites would need to be released, and the number and frequency of pesticideapplications also would be reduced. This strategy also would provide less opportunity for DBM todevelop resistance to pesticides (ref. www23).79 Cabbage Ecological Guide - 2000