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Parasitic Wasps Protect TFP’s Tomatoes

Tomatoes in the Dudley Greenhouse
Tomatoes in the Dudley Greenhouse
In the back bay of the Dudley Greenhouse, past the seedlings and the community beds, hundreds of tomato plants are just reaching maturity. We call this part of the greenhouse the "Enterprise Bay." Later this week, Greenhouse Manager Danielle Andrews and Community Food Associate Jennie Msall will harvest the first batch of tomatoes. The tomatoes will be sold to restaurants in Boston and Cambridge and the revenue will contribute to the cost of operating the rest of the greenhouse.

The tomatoes were planted as seedlings in late March and cared for by Danielle, Jennie, TFP's youth interns, and several dedicated community members. Over the past several months, pests such as aphids, spider mites, and thrips have attacked the tomatoes. Each of these pests have been managed through IPM, or integrated pest management, strategies. IPM strategies use information about the pests' life cycles and interactions with the environment to control pests in an ecologically sustainable way. For instance, the tomatoes are sprayed regularly with a soap mixture to irritate and kill pests.

To control the aphids, The Food Project purchased wasps called Aphidius colemani from IPM Laboratories. The wasps arrive dormant, in beakers. The beakers are placed in the soil underneath the tomatoes to warm slowly. As the wasps warm, they fly up to the tomato plants in search of aphids. The wasps are parasites, meaning that they rely on another species for survival. In this case, the wasps lay their eggs inside the aphids. The egg hatches and the wasp larva slowly eats the aphid from inside. The adult wasp then emerges from the aphid skeleton, often called an aphid mummy, and flies out in search of another victim. A. colemani provide excellent pest control for greenhouses because they have high reproductive potential. Each female A. colemani wasp lays an average of 388 eggs in her four to five day lifespan. In addition, the searching behavior of the adult wasps disturbs aphid colonies and often causes aphids to fall off of the tomato plants.

Tomato harvesting will continue in the Dudley Greenhouse through the end of July. We are excited to have a delicious and abundant harvest! For more information about the Dudley Greenhouse, please contact Community Food Coordinator Danielle Andrews.

 

Check out these websites to learn more about A. colemani wasps and integrated pest management: http://www.entomology.wisc.edu/mbcn/kyf502.html, http://www.epa.gov/opp00001/factsheets/ipm.htm.

 

 

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