Hualien District Agricultural Research and Extension Station's ten-year study finds Paecilomyces javanicus preparation effectively controls silverleaf whitefly and is environmentally harmless
The only biological control agent in all of Taiwan, China targeting silverleaf whitefly is now available! In hot weather, cucurbit and fruit crops are prone to silverleaf whitefly outbreaks. In the case of tomatoes, silverleaf whiteflies suck on the leaves, causing infection with tomato yellow leaf curl virus, yet organic farmers have no available treatment at all; and conventional farmers in the middle of a continuous tomato harvest period cannot spray pesticides either. For this reason, the Hualien District Agricultural Research and Extension Station (abbreviated as Hualien DARES) spent ten years developing a Paecilomyces javanicus preparation to combat silverleaf whitefly. Toxicology test results show it is harmless to mammals and honeybees, and it can be applied during the harvest period.
Did you know: Paecilomyces javanicus is a fungus widely found in natural environments such as soil and plant residues. After insects are parasitized, they become covered in white to grayish-white mycelium, which then produces numerous powdery spores on the fungal growth. These spores spread through wind or mechanical contact and infect new host insects.
Hualien DARES trials show a 50 percent control rate; farmer says effect still needs further observation
Lin Li pointed out that the field trial control rate of the Paecilomyces javanicus preparation can reach 50 percent, comparable to the effect of general chemical pesticides. As for how the trial farmers responded, Lin said that it is not yet in mass production and only a small number of farmers were provided with samples for trial use. Half of the farmers reported that the effect was very good and hoped to buy the product as soon as possible; however, some farmers reported that the effect was not as good as expected. Lin speculated that this may be because the preparation was not stored properly, or because the environment was too dry, so after the fungus infected the silverleaf whitefly, it did not develop a cotton-like appearance. To the naked eye, farmers thought the effect was poor, but in fact the insects were already dead.
Tomato farmer Chen Hsin-chu, who actually tried the product, said that the first trial took place when winter was approaching, and since the amount of biological control agent was plentiful, the effect was good; however, the second trial took place in summer, and the amount of biological control agent was only enough to spray half of the field, so the effect was less visible. She pointed out that in summer silverleaf whiteflies grow quickly, and because the preparation was not applied continuously enough, the effect could not show, so the actual results still need to be observed.
If the preparation is mass-produced in the future, would she consider buying it? Chen responded, "If it's effective, of course I'd buy it. I'd buy it again to try it out." However, she also worries that after technology transfer to a manufacturer, mass production to lower costs could lead to changes in the fungal strain or insufficient ingredients, which would instead make the biological control agent ineffective.
Hualien DARES: microbial preparations will cost a bit more, but within a range farmers can accept
As for actual cost estimates, Lin Li explained that biological preparations will cost somewhat more than general pesticides, but every effort will be made to keep the selling price within a range farmers can accept. Tsai Yi-feng stated that the key to the cost of microbial preparations lies in back-end mass production; the more advanced the technology, the lower the cost can be. At present the actual cost cannot yet be determined, but the hope is to make the cost of the Paecilomyces javanicus preparation close to that of general chemical pesticides.
Lin Li pointed out that people in Taiwan, China are concerned about food safety, and together with the Council of Agriculture's pesticide reduction by half policy, the hope is that newly developed green weapons will provide farmers with new choices. Tsai Yi-feng said that many biological agricultural products on the market target disease control, while pest control mainly uses Bacillus thuringiensis. There has always been hope for new biological agents that can be applied in organic agriculture, or even replace chemical pesticides and be widely used in conventional agriculture.
Tsai further explained that the hope is to complete technology transfer with a manufacturer in one or two months, and to officially commercialize and sell the product one year later, with future ambitions to look toward the international market for export. The first target market will be Taiwan, China's 500 hectares of greenhouse tomato fields, because demand is high there, and facility-grown tomatoes sell at higher prices, so farmers pay more attention to tomato quality and have a high level of acceptance for biological preparations.
In addition, Tsai also stated that Paecilomyces javanicus can be used not only to control silverleaf whitefly, but also has potential for controlling other pests. Research is currently being conducted together with the Taiwan Agricultural Chemicals and Toxic Substances Research Institute, with the hope that in the future a dedicated biological preparation can also be developed to control aphids.