Fighting A Bug To Make Food Local Again
Grant Blankenship/Georgia Public Broadcasting
On a day when the bounty of summer vegetables were heaped in farmer’s stalls, Amanda Chester was on the hunt for one thing.
“You ain’t go no purple hulls yet?” she asked farmer Woody Nix at his stall at the Mulberry Farmers Market in Macon, GA.
“I sold all I had picked the other day,” he said, “Pretty ones, too.”
“Aw, man!” Chester exclaimed in disappointment.
Chester’s “purple hulls” were purple hull peas. You probably know them better as black eyed peas. Scientists know them, along with crowder peas, zipper peas and others, as cowpeas, or Vigna unguiculata. Chester, like generations of Southerners before and after her, grew up with them.
“My grandfather was a sharecropper. We raised plenty,” Chester said. “Oh, they just taste so good!”
Whatever you call them, Cowpeas help define Southern cuisine.
Cowpeas were domesticated in west Africa five thousand years ago. They came to the Americas with the slave trade. At one time, Georgia alone grew seven times the cowpeas grown in the entire nation today. Tens of millions of acres are grown in Africa, but in North America this staple of the Southern plate probably comes from California. Or, perish the thought, maybe even Canada. How did that happen?
David Riley has some answers. He is an entomologist with the University of Georgia down at ths school’s south Georgia campus near Tifton. A few miles away from his office there is an experimental field where he is working on one piece of the puzzle of cowpea collapse.
At first glance, it didn’t look like the scene of a biological battle.
“This is a massive weevil population, even though it doesn’t look like much,” Riley said.
What it looked like were a few rows of sandy soil. The peas had been picked and the rows were plowed under. Yellow and green weevil traps of various heights were parked on about half of the plot. This crop was done. It had been given to the weevil known as Cowpea curculio.
This is what Southern farmers have done with weevil infested cowpea plots for hundreds of years.
“They said well I’m done with it let’s mow it, plow it under and get ready for the next season,” Riley said.
Cowpeas can stand up to drought, extreme heat and terrible soil but not to this bug. The payoff in dealing with the bug has been a cheap to grow pea that is among the most protein laden of any legume around. It pulls nitrogen into the soil from the air, so it needs little fertilizer. David Riley tells a story about one cowpea plot that got no water for weeks. He expected those plants to burn up in the sun only to find they had outlasted the weeds around them.
Weevils and people agree, there’s a lot to love, but weevils are tough. Adult weevils have defeated every pesticide thrown at them.
“Like I say, they’re like little tanks,” Riley said.
It turns out the baby weevils, the grubs, do the damage. Donnie Cook, the farmer who tends this plot, dug into a pea pod with his thumbnail until he found one.
“He’s real wiggly,” Cook said.
It looked like a twitchy grain of rice. The grub left a hole in the pea, called a sting by farmers. It makes the pea inedible, or at least unfit for the fresh vegetable market. After eating the pea, the grub would have dropped to the ground to grow up.
“And about three weeks to four weeks later, these guys will come out of the soil,” Riley said.
They come out of the soil as adults ready to make more babies. Until then, the grubs are vulnerable, stranded above ground.
Riley says giving up and plowing in as farmers have always done just gives the grubs a free ride to underground safety. He says if you want to save half of your next pea crop, don’t plow, but strike.
“They do have an insecticide that works on the grub, not the adult but the grub. And that’s Lorsban,” Riley said.
Riley thinks that spraying stranded grubs with Lorsban might short circuit the life cycle and improve cowpea yields. However, Donnie Cook says its tough convincing farmers to spray land with no plants for bugs they can’t see after a harvest.
“It’s a hard sell after they’ve done got out what they gonna get out,” Cook said.
The argument becomes even harder when farmers are told that whatever they are growing above ground, they are also growing Cowpea curculio weevils below. The insect can hang out in a variety of environments until it runs into its preferred food again. For Riley’s approach to really work, he is asking farmers to consider treating a field they may never grow cowpeas in for the sake of their neighbor who does. Or even their neighbor’s neighbor.
That kind of cooperation is not unheard of though. The scourge of the boll weevil, which threatened to make cotton a past tense crop in the United States, rallied farmers to very similar efforts in the 20th century. Of course, cotton is a commodity in demand everywhere. Cowpeas are not.
Nevertheless, controlling this Cowpea curculio could make the difference between Southern cowpeas as a farmer’s market specialty and a crop you could rely on again in times of drought and extreme heat.
For David Riley, this is also about legacy.
“I look back at my predecessor in this job, and he worked his whole life, but at the end, the insect won,” he said “It did! The insect won!”
Riley said it’s nothing personal, he really loves weevils, but for the sake of the cowpeas he can’t let them win.
