JAPANESE BEETLES ARE HERE!...
Yes, the Japanese Beetles are here, but not everywhere. This beetle is the only plant parricide of the grub larvae produced beetles. Japanese Beetles will eat just about any vegetation, but particularly like roses, hibiscus, linden and petunias, so these are good plants to keep and eye on. Once they hatch out of the ground, they will feed for 3 to 4 weeks depending on weather and food supplies.
The Japanese Beetles’ life cycle goes from mating and egg laying (the adults lay their eggs in the ground) in June and July. Those eggs hatch in late July and August into the larvae stage or grubs which like an earthworm digests organic matter in the soil but when organic matter is in short supply they feed on roots. The grubs feed until the ground starts to freeze, then they tunnel deeper into the soil to avoid dying over winter. In the spring they feed for a short time then go into the pupa or cocoon stage until June when they come out of the ground as adults and start the cycle again.
Now that you know their life cycle, here are some tips on how to eliminate them from your lawn and garden:
1. Traps! I know that some people say that they bring more beetles, but with proper placement they remove the beetles from your desirable plants and trap them and keep them from reproducing for next year. Please be sure that you put the traps out in the yard away from your beds or the plants that you are trying to protect. For every adult beetle that doesn’t lay eggs, you reduce next years population by tens to hundreds without chemicals!
2. Pyrethrins are an organic insecticide from the flower of the pyrethrin daisy plant. Pyrethins are effective on Japanese Beetles because it is both a stomach poison and a contact killer. You want to spray in the evening for two reasons: one the beetles feed more at night and two the spray is weakened by sunlight, so it lasts longer and more effective in the evening. One draw back to using pyrethirn sprays is that you have to repeat every three to four days.
3. Permethrin is a synthetic pyrethrin that works the same way but because it is man-made it lasts longer so that you can wait seven to ten days between applications.
4. Systemic insecticides are very effective on Japanese Beetles when applied prior to the outbreak of the beetles. These chemicals take ten to fourteen days to get into the system of the plant for maximum effectiveness. The spray will have some effect on beetles that are present during spraying and right after but will be less effective until it starts moving though the plant.
What ever method you choose to use make sure that you identify the problem, and if you’re not sure what you’re dealing with bring in a sample and we can tell you what you have and give you options as to how to correct it.