The USU Student Organic Farm:
Our Methods for Coping with Pesky Plant-eaters
An organic farm has many enemies: artificial fertilizers, lack of soil fertility, never-ending paper records, unimpressed certifiers, pesticides, and yes, pests themselves. A farmer’s pests can come in all shapes and sizes; from the large and hungry deer, to the tiny flea beetle. But, deal with the enemy we must, if we are to successfully bring delicious organic produce to our CSA member’s door.
At the Utah State University Student Organic Farm, we have different methods ranging from not very effective to somewhat effective for dealing organically with the insects that call our farm home and feeding-ground. These include physical barriers like row cloth, mechanical measures which mostly consist of plucking them up and squishing them, biological methods including trap crops and baits, organically approved pesticides, field management through the seasons, and finally, patient acceptance of some lacy greens.
The little fiends that we know well on our farm include flea beetles, grasshoppers, slugs, Mexican bean beetles, and aphids. Flea beetles feast on younger leafy seedlings and on mustard greens and arugula. Grasshoppers eat everything from Swiss chard leaves to cayenne peppers to green onions to tomatoes. Slugs are usually found munching the undersides of lettuce leaves. Mexican bean beetles, true to their name, are found on the underside of bean leaves, leaving them splotchy and hole-ridden. Finally, aphids tend to attack the undersides of young leaves in seedlings and seem to have a particular appetite for kale and broccoli leaves.
The USU student organic farm is run entirely by students with advisory help from Drs. Jennifer Reeve and Dan Drost. Kale (bottom) is sometimes hard hit by aphids, flea beetles, and grasshoppers.
One effective control method we have found is to put a physical barrier between the plants and insects in the form of row cloth. Assuming this cover doesn’t have holes and is kept tied down close to the soil, it is fairly effective at keeping grasshoppers and some flea beetles away. Unfortunately, flea beetles emerge from the soil and hang out near the roots of plants so this method isn’t as effective with them.
Squishing insects is effective for the individual but not so much for the population; though we do use this method on grasshoppers and Mexican bean beetles. Trap crops are supposedly effective at diverting the masses from the main crop of a farm by giving them a more desirable crop away from the farm’s main vegetables, but we found that flea beetles seemed to partake in the trap mustard greens as an appetizer before bounding onward to our main crops. OMRI (Organic Materials Review Institute) approved pesticides and chemicals are allowed on an organic farm, but we’re always a little hesitant to use something that could potentially harm beneficial insects, especially bees. However, we did use Semaspore Bait, which is a bran bait that contains a naturally occurring pathogen of grasshoppers, and found that we need to treat a larger area next year for better results. For aphids, we found some homemade solutions to be fairly effective including soapy water for broccoli and a cayenne-pepper mineral oil solution for kale, which enabled it to grow back after being nearly destroyed.
The Mexican bean beetle, a lady beetle relative, may look cute, but is a voracious plant pest.
Crop rotations are a significant part of organic farming for a variety of reasons. This process, both in rotating between two fields and in rotating placement of vegetable type within the field, not only aids in soil fertility, but also decreases certain pests. Planting the same family of vegetables in the same place year after year results in a larger probability of insects and diseases that attack that vegetable group; they can lie in wait through the winter and have their preferred meal choice easily accessible the following season. Crop rotation helps to avoid this problem.
Some of our attempts at organic solutions to pests work fairly well; others seem to make no difference at all. Sometimes all we can do is wait out a pest, such as flea beetles, which slow their attack when the weather gets hot. Ultimately, we monitor, intervene where we can, and hope that enough of our produce manages to survive for harvest.
-By Amanda Hawks, Farm Intern and summer co-manager of the USU Student Organic Farm, located on 800 East in Logan, Utah. On 1 acre and in 2 hoophouses, the students grow dozens of vegetable varieties and run a CSA and a fresh market stand on campus, which serves 55 or more customers in the Cache Valley. To find out more about the farm, or to join the CSA for 2013, click here or email them at firstname.lastname@example.org.