Pests and pollinators can be managed simultaneously on watermelon farms, reducing insecticide applications and improving yield.
In field trials, researchers led by Ashley Leach at Ohio State University tested commonly-used insecticide products using either a weekly application or based on population thresholds of the striped cucumber beetle (Acalymma vittatum) – a key pest of melon.
The initial trial showed that a threshold-based approach delivered a statistically-similar level of pest control to the weekly programme, while requiring between 20 and 80% fewer insecticide applications and bringing in 42% more pollinators to the crop.
Multiple advantages
The integrated pest and pollinator management (IPPM) approach was validated in a follow-up trial at commercial scale, using acetamiprid, the pesticide associated with lowest toxicity to pollinators. A threshold of two beetles per plant was set for application, with regular monitoring to determine numbers. In control fields, farmers used their regular application program.
The IPPM fields saw 62% more pollinator visits, and 49% more melons at harvest. Only one of five fields using IPPM programs required a pesticide application over the growing season, while farmers’ own programs ranged from two to eight applications.
Broad potential
The work has implications for other pollinator-dependent crops, Leach told Farming Future Food.
“It’s possible to find similar trends in other crops, and there are some early indications of this in apple,” she said.
Successful application of IPPM would represent a ‘win-win’ proposition that would likely be attractive to many growers, given issues such as pest resistance to available insecticides and declining natural pollination services.
“I think many growers are open to threshold-based programmes, but like anyone, they want to be shown the data that supports the claims,” Leach continued.
“This study is an exciting step towards supporting that goal. Not only are we seeing effective pest control but potentially increased pollination.”
Other threshold approaches worth considering
A threshold-based approach to pesticide application has also been recently suggested by researchers in Finland – although with a different focus.
The University of Helsinki team modelled applications based on counting natural enemies of a pest in the field, finding that, similarly to what was seen in the present study, such a dynamic system always resulted in reduced spraying of crops.
