Controlling spread of Parthenium in vacant lands has for long been a challenging task not only for officials, but even for residents in their vicinity with many of them susceptible to severe allergies.
In an novel attempt the Horticulture Department officials have left leaf-feeding beetle Zygogramma on the parthenium which has grown in large hectares of land of Linganbudhi Lake.
The Zygogramma insect was released in the vicinity of the lake around three months ago and the insects have multiplied into thousands. These insects have been successful in eradicating pathenium in around 40 per cent of the surroundings of the Linganbudhi Lake, by eating leaves and flowers of the parthenium.
“The use of insects to control spread of parthenium is a naturally phenomenon. Spraying of pesticides destroys leaves and not seed. Meantime, pesticides makes soil toxic,” say officials.
Horticulture Department Assistant Director Balu BP Gowda informed that they collected around 40 insects found feeding on Parthenium plants growing on vacant places and left on the land of lake. The insects in a short time of 30 days have reproduce in thousands, he adds.
“Zygogramma is an accepted biological weapon to control growth of parthenium weeds. As these beetles feed on Parthenium plant it begins preventing pollination and new growth. The insects are found in the open only at certain places and will not harm other cultivated crops. Anybody can collect the insect on their own and release the same in places infested with Parthenium. So that it can be completely eradicated," he added.
"Parthenium weeds grow and spread very quickly within no time. The insect prevents production of seeds produced by parthenium weeds by eating flowers. This helps in prevention of allergic reactions and other health hazards caused by parthenium weeds," says another official.
* Parthenium Hysterophorus weed was brought to India along with PL480 Mexican wheat seeds when they were imported in 1950s.
* The Indian Institute of Horticulture Research introduced the leaf-feeding beetle Zygogramma Bicolorata (Coleoptera:Chrysomelidae) also brought from Mexico in 1983.
* Necessary permission for conducting field trials were obtained from the Plant Protection Advisors in 1984.