Over the next several weeks, first generation codling moth will be the primary concern over the region. For those considering preventive control of the European red mite (ERM), optimum timing of a miticide application is any time in the next couple of weeks.

Codling moth degree-day accumulations range from about 230 in Henderson and Wilkes Counties to 370 in Cleveland County. In lower elevations (e.g., Cleveland County), now is good timing for an initial application under low population densities. In Henderson and Wilkes Counties, initial egg hatch is predicted to occur later this week, which is the optimum timing in orchards with moderate to high populations. In orchards with low populations, an initial application can be delayed until about 350 DD; based on the forecast 350 DD is predicted to occur later next week.

Refer to last week’s update for more information on timing of applications and choice of insecticides for codling moth.

For those preferring to manage ERM preventively with a miticide, those applications can be applied any time over the next several weeks. Timing based on a specific cover spray or date is less important than the mite population at the time of application. Populations should be low (less than 1 per leaf) for the most effective control. Mites are currently at very low levels – so low that they are not detected using standard sampling programs. It is rare for ERM populations to build to detectable levels before mid May, so applying a material any time between first or second cover is ideal.

Below is a list of miticides recommended for preventive control. Annually rotating materials from different mode of action (MOA) groups is an important resistance management strategy. Note that Apollo and Savey (Group 10A) and Zeal (group 10B) are all mite growth inhibitors. Surveys in Henderson County over the past two years have shown that cross resistance between these two subgroups (10A and 10B) does exist, so treat all three of these miticides as the same product for rotational purposes.

It should also be noted that ERM surveys during the past two years in commercial apple orchards have found high levels of predatory mites. In many instances the biological control provided by predatory mites has been sufficient to keep ERM populations below damaging levels without chemical control.

Learn more about southeastern apple insect pests at the Apple Insect Management page.

About degree-day models