Bacillus thurengiensis (BT) is a natural bacterium that is widely used as a safe and effective pesticide.
Current approaches used by farmers to control pests in cabbage crops are failing. More pests are emerging, pesticide abuse is rampant, and pesticide residues are often detected on cabbage at the market. In response, the Indian Council of Agricultural Research (ICAR) called a meeting to discuss innovative and sustainable approaches to cabbage pest control. Representatives from environmental, regulatory, research and consumer communities in India attended.
Dr. O.P. Dubey of ICAR presented the background to the issues faced. He reported that the number of pests attacking cabbage in India has increased from 10 to 38 since 1920. This is despite the use of pesticides, pheromone traps, trap crops, pest-resistant varieties, and other pest management strategies. Although the volume of pesticides used in India has declined from 75,000 MT in 1990-91 to 43,600 MT in 2001-01, pesticide abuse is rampant and pesticide residues persist as a major problem (12% of vegetables at the market have unacceptable levels of residues).
Native to the Philippines, the oriental fruitfly (Bactrocera Philippinensis) is a very destructive pest to edible fruits like mango, guava, breadfruit and papaya.
Eradicating the fruit fly using bait control could be done in two stages using the Male Annihilation Technique (MAT) and the Sterile Insect Technique (SIT). First, the researchers reduced the population of male oriental fruit flies to a minimum so that mating would not occur. Male oriental fruit flies were trapped using methyl eugenol- a powerful male attractant, with an insecticide such as Naled (Dibrom) or Fipronil.
Cordelitos (lengths of 6-ply cotton string about 30-45 cm) or caneite (compressed fibreboard) blocks (50 mm x 50 mm x 12.7 mm), or coconut husk blocks (50 mm x 50 mm x 10 mm) were soaked in the bait material and distributed in the field at 400 pieces per square kilometer. This treatment was repeated every eight weeks. The baits were placed on top of tree trunks or wooden poles, well out of the reach of children or animals. This technique is called the Male Annihilation Technique (MAT).
Then the residual fruitflies were eradicated using the Sterile Insect Technique (SIT) or the sterile male technique. Sterilizing insects is a new technique where insects are either treated chemically, genetically, or with radiation to be infertile. In the case of male fruit flies, they are subjected to radiation to make them sterile. The method aims to wipe out the fly population by introducing sterile males that cannot produce any offspring when they mate with the female fruit flies.
Sterile flies have been used in many countries. In the past, both male and female flies were released. Sterile female flies’ eggs did not develop, however, some skin damage to the fruit did result. To counter this problem, the United States Department of Agriculture (USDA) developed a genetic technique that separates males from females in several fly species. Flies released in Hawaii were only male sterile flies. Continue reading “Eliminating the pesky fruit flies”