Evaluation of Sevin

We hesitated to use Sevin on our vines, but changed out minds as soon as we saw the damage that would be done by the Japanese Beetles. So far Sevin seems to be fairly effective at preventing massive damage by JB. The end of May brought swarms of newly developed JB and they immediately started attacking the leaves on the vines. An application of liquid Sevin killed any JB that ate at the leaves and, we hope, dissuaded others from even attempting.

On the July 4th weekend I had a chance to look over the vines and inspect the JB damage. I found that some vines had many dead beetles around the base and some had very few. I dont know why some vines are targeted and others not. It may be that the targeted ones were simply chosen randomly at first or chosen because they had particularly attractive leaves and the other JB just followed suit. This would make sense because JB excrete a substance while feeding that attracts other beetles to the location. None of the vines had serious damage. Many had a few leaves that had holes in them.

While I was walking down the rows I did see a few beetles who were munching on the leaves. The interesting thing was that every JB that was actively eating, or, I presume, had been eating was acting strange. Most of the JB were hanging on only by one arm and one leg; the rest of their body was flailing in an effort to stay on the leaf. It was funny and satisfying because I interpreted this as the poison working. I dont wish death on anything, but I can make an exception for the JB; especially considering that it serves no purpose and offers no value to nature.

The JB that were fimly attached, and, I assume, not eating, I grabbed, threw to the floor and quickly ended their lives with my shoe.

My first impression is that the Sevin is working well. There are few JB attempting to feast on the leaves and those that do die quickly before much damage can be done. Most of the leaves are still green and healthy with little damage. The leaves outside of the grow tubes are starting to flourish, while the leaves inside the grow tubes are starting to die or turn odd colors (this fact convinced us to start taking the grow tubes off b/c eventually we will remove the leaves from the trunk anyways). I did still see activity in the vineyard from other insects and animals. I saw a few frogs and many spiders and flies. I was scared at first that the Sevin would drive the beneficial insects and animals away, but so far the impact has appeared to be minimal.

The negative to Sevin is the impact that it has on life in the vineyard. I found a few dead Ladybugs around the vines last weekend. I dont know whether their death can be attributed to Sevin, but it does seem like it could be more than a mere coincidence. I had hoped to maintain a healthy balance of pest and beneficial insect. I have no idea if the Sevin is driving beneficial insects away, which will lead to an influx of pests. I am also concerned about the Sevin getting into the ground and into the roots of the vines. The vines wont bear fruit for two more years, but I fear that there might be some lasting effects of using Sevin that show up in the fruit sometime down the road.

Overall we could not have made it through the summer without the Sevin. Later this summer we will apply some Milky Spore to try and kill as many grubs as possible to obviate the need for Sevin next summer. We will also experiment with Neem oil next year and see how that works.

Next up:

Pruning and training the vines.