Thursday, July 23, 2009

Love, life and death in the cowpea patch

I have three kinds of cowpeas (also known as black-eyed peas or southern peas) in the garden: "California Blackeye #5" from Botanical Interests, and "Pinkeye Purple Hull" and "Big Red Ripper (Mandy)" from Southern Exposure. I am also growing an asparagus bean called "Stickless Wonder" from Evergreen Seeds. This bean is actually in the cowpea family, and the plants look quite similar. Most books I have read theorize that cowpeas originated in Africa, and their affinity for our hot humid weather seems to support that idea.

Cowpeas start easily from seed, and quickly grow without any fertilizer and very little watering. The California Blackeye's were the first seeds I planted, and one of my first harvests of the year. I have already collected a good quantity of peas. The peas are drying in the kitchen now waiting to become a tasty southern dish.

I have been spending so much time hunting for Squash Vine Borer eggs and caterpillars, my cowpeas have had to survive without much attention. The plants have always been so healthy, I really didn't do much beyond looking for new pods to harvest. Yesterday I noticed one of my pinkeye plants was suddenly on the verge of death. My formerly vigorous plant had turned brown and sickly. When I looked closer, I saw the plant was covered with dark aphids. Even worse, the aphids were all over the tips, flowers, leaves and pods of almost every pinkeye plant, and big black ants were scurrying up and down harvesting the aphids' honeydew. To add insult to injury, I was stung by an ant protecting its herd when I grabbed a stem to inspect the aphids. I ran to check my other plants, and was dismayed to discover hoards of aphids and ants on my Big Red Ripper, California Blackeye and Stickless Wonder plants too. Overnight, the aphids and ants had staged a coup and taken over my cowpeas.

I soon learned that my invader is a cowpea aphid. Who knew there were so many highly specialized insects -- first the squash vine borer, and now a cowpea aphid. Apparently, the aphids are attracted to a nectar secreted by the plants. They have found paradise in our back yard.

Hidden among the ants and aphids were several ladybugs. I even discovered a ladybug pair locked together, mating on a cowpea stem. The female was gorging on aphids while the male did his business. Ladybugs are a useful ally in the garden, but they seem to be working rather slowly. Perhaps our ladybugs are too consumed with matters of the heart to annihilate the aphids.

With no other help in sight, I started removing the aphids by hand, a tedious and gorey method. After half an hour, my hands were dark with aphid viscera, the ants were in hot pursuit, and I was overwhelmed by the task at hand. I had barely finished cleaning up my pinkeye plants, but I was worn out. Even though the aphids are tiny, they have numbers on their side. I now have a garden pest that may rival the Squash Vine Borer for the title of Vegetable Garden Enemy Number One.

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