management via confusion
Apr/30/2012 07:30 PM Filed in: orchard
Our orchard is now a cloud of female codling moth pheromones, which will hopefully lead the males so astray they can’t find any females to mate. This weekend we put almost 800 little pheromone dispensers in and around the orchard, with the remainder to go in tomorrow. We are relying on this mating disruption to control this pest rather than the Bt we have relied on in previous years, since a) Bt kills any moth or butterfly caterpillar that eats it, which is not as directed a control method as we would like, and b) Bt is not very effective on codling moth, since they spend most of their time eating inside apples, where there is no way to dose them with the Bt. Mating disruption is well-tested in large, flat expanses of orchard, but some growers with small orchards have had good luck as well. Our site presents a number of challenges - slope, wind, lots of untended apple trees in the neighborhood - but we figure it is worth a try, since the alternative doesn’t work that well. We will continue to pick up and store all damaged apples until the caterpillars die - our thinning buckets always have codling moth larvae in the bottoms when we dump them out.
Some apple blossoms have opened, and we appear to have escaped the cold temperatures of the last few nights with very little damage. This is despite lows of 27-28 degrees, which should kill 10% or more of the blossoms. We have so many flowers on the trees this year, a little frost thinning would be ok. While we still have a month to watch for frost before that danger has passed, we are glad to have gotten through this cold snap with apples still growing.