Sweeping

     In the alfalfa fields of Owyhee County (and most everywhere else) the farmers are spending a lot of time sweeping. No, not with a broom, with a net. The farmer goes out into the field and runs the net through the alfalfa in a 180 degree arc. By doing this, the farmer can get an idea on the ecosystem therein. Here are a few things that can be found.

     A penny! Just kidding, the penny was added for scale. It's the insect on Abe's ear that you'll find a lot of.
It's a Pea Aphid. Pea aphids are sap suckers. That's like a mosquito, but for plants. As you can guess, they're bad, as are their offspring.

     They're quite a bit smaller than the adult stages, but just as bad. Fortunately there are not enough to be a problem. Once their numbers reach a certain threshold (as dictated by the IPM) they will need to be dealt with.

     This picture contains all kinds of stuff. Starting from the top left, there is a housefly, who just happened to land there as I was taking the picture. Houseflys have very little effect on alfalfa. Just to the right of the housefly is a Lygus Nymph. A lygus nymph is the same size as the small aphids, but much more energetic. When the net is opened up, they run for cover. Below the nymph is an alfalfa flower and in the bottom corner is another aphid.

     Field sweeping is not just a census of harmful insects. This is a Minute Pirate Bug, (Yarr) and it enjoys sucking the tasty juices out of small insects such as the aphids and lygus nymphs. The strings of the net should indicate to you that he's a very small bug and won't harm anything of any size.

     Also a beneficial insect is this Damsel Bug. Not the dainty kind of damsel, this bug likes to spring on its victims and tear them all to bits. A fitting end to a pest if you ask any farmer.
     Keeping an eye on the ecosystem in the fields allows a farmer to most efficiently decide where and when to interfere. This is a major part of the IPM. (remember the IPM?) It is more cost effective to leave a certain amount of pests. The beneficial insects curb their growth, but when the pests get too numerous, the farmer can then take action. Sweeping keeps the farmers informed and helps them to decide when that action should be.