Free and interactive online courses are available for ctirus pests at the UC ANR online learning site http:class.ucanr.org. Each of the six modules takes about an hour to complete. If you pass the quiz with at least a score of 70% then you earn 1 continuing education credit for each module. Check them out!
We have been treating citrus seedlings and releasing Fuller rose beetles adults onto them to see which insecticides might be effective in killing them. We are not seeing a lot of mortality. For some insecticides, rather than die, they avoid feeding on the treated foliage and they can live a long time without feeding. More details to come when we have the data analyzed........
During the past few months we have been testing adult female earwigs with various insecticides using a petri dish bioassay method. We are finding that very few insecticides kill them quickly and completely: Lorsban Advanced and Danitol worked the best. There is a spinosad bait called Seduce that is very effective in the laboratory but did not work in a field trial because the earwigs were up in the trees and did not feed on it. We are continuing to study this product to find out when and how to apply it to make it effective. We have also found that if we leave earwigs in petri dishes without food and water they can live for more than 3 months! These are very tough insects.
While surveying a site for Fuller rose beetle, we observed a number of dead beetles with their heads broken off. We were wondering what might be predating on them, and I caught this spider in the act. I was disappointed that I did not get a photo of the spider feeding (it dropped the beetle when it saw me), but I did see the spider with its mouth inside the body of the beetle. The mystery is solved! Its good to know that something is working on the beetle population.
Fuller rose beetles are a primarily a problem because they lay eggs under the calyx of fruit and those fruit can be rejected when exported, because some export countries don't want this pest to establish in their region. Fuller rose beetle can also cause significant leaf damage to newly topworked orchards. We have been sampling an orchard near Lindcove and, while a few beetles emerge year round, we are seeing heavier numbers emerging as of the first week of August. You can find Fuller rose beetles first by looking for notched leaves (edges chewed) and frass (insect feces), then look for the adult beetles inside curled leaves. They love new flush and leaves rolled by leafminer damage. They tend to be on the lowest branches of the tree. You can also survey for them by putting a beating sheet or tray under the trees and shaking the adults out onto the tray.