What is in this article?:
- Papaya plants play key role in greenhouse whitefly control
- Problem solved
• The major issues involved with this whitefly are its ability to transmit viruses and to become resistant to most pesticides.
• Whiteflies feed on tomato leaves and transmit diseases, including tomato yellow leaf curl virus.
• By introducing papaya plants with wasps into the greenhouse before any pest whiteflies are detected, the wasps act as sentries and attack any whiteflies that might become established in the crop.
Osborne and his team solved the problem by introducing papaya plants into the system. The papaya plants come with a whitefly that’s specific to papaya but not a pest for tomato or other crops, thus allowing the wasps to survive.
The researchers found the wasp significantly controlled silverleaf whiteflies on tomatoes while at the same time preying on papaya whiteflies.
The wasps were able to fly from papaya plants located in the corners of greenhouses to attack silverleaf whiteflies on tomatoes located in the center. Successful tomato production occurred without the use of pesticides.
“This system has the ability to be just as effective as insecticide controls,” said Osborne, a member of UF’s Institute of Food and Agricultural Sciences. “The idea is not to limit insecticide use completely, but to have plants that don’t have resistant whiteflies and ultimately, not any whiteflies at all.”
Insecticides can be used, but with fewer applications, Osborne said, as part of an integrated pest management system that uses the best methods available to solve pest problems while mitigating negative environmental effects.
The system is known as a banker plant system because it stores, or banks, extra prey for the biological control organism. The wasp works by laying eggs in immature whiteflies, killing the whitefly when the wasp offspring hatches inside of it and feeds on its insides before emerging.
Yingfang Xiao, a postdoctoral associate researcher and lead author on the study, said the papaya plant also has the potential to host other biocontrol agents, such as predatory mites and spiders.
“It could be possible that papaya may support multiple natural enemies for controlling multiple pests,” Xiao said.
The system has been used in a commercial herb, tomato, cucumber, eggplant and lettuce greenhouses around the state well as in a commercial poinsettia greenhouse, where it has also been effective.
For now, the system is limited to Florida, as papaya has tropical and subtropical climate requirements and moving the papaya whitefly across state lines is illegal. However, Osborne said his team is looking for another whitefly and host plant that could be used by growers in other regions.
The U.S. Environmental Protection Agency funded the research.