The Oita Prefectural Agricultural Research Center in southwestern Japan has completed a project designed to develop technology for exterminating spider mites, a pest that damages fruit such as strawberries, by using its natural enemy, Phytoseiulus persimilis, a spider mite predator. In September 2004, the Center will begin verification testing with the cooperation of strawberry growers. It is also planning to compile a manual for eco-friendly pest control by the end of fiscal year 2005 (ends March 31, 2006).

Spider mites eat and damage the leaves of many kinds of crops, degrading crop quality and reducing yields. They are so minute and hard to find that it is often too late by the time they are discovered on the crops. So far they have been exterminated using pesticides, but because they appear during a medium to long period during the crop growth, they easily become pesticide-resistant. Thus, there is a need for an extermination method that allows the minimum frequency of pesticide application.

The newly developed method using the spider mite's natural enemy has several merits, including significant labor-saving in pesticide application, longer duration of effect, minimized chances of the spider mite's developing pesticide resistance and, above all, a sense of safety for consumers buying farm products grown with this method. However, it has not come into wide use so far because it is difficult to properly manage the timing, amount and frequency of introductions of Phytoseiulus persimilis, and also because it requires expertise to control humidity and temperature in greenhouses where the fruit is grown.

The Center has successfully reduced spider mite extermination costs to one-third and work hours to one-twelfth compared to conventional methods, but it has not yet eliminated the damage during a certain period in the early stages of cultivation. While extermination by pesticides produces a rapid effect, the natural enemy method, requires growers to wait patiently while the predators propagate, says Shinichiro Okazaki, a researcher for the Center. He adds that their efforts, however, will eventually expand to other crops, as demand for safe agricultural products is growing.



Posted: 2004/10/26 11:42:15 AM
Japanese version

TAG Ecosystem , Food/Water , Technology , University/Research institute