Rainy Weather Means Apple Scab and More Apple Scab

This 2018 growing season thus far is proving to be one of the more severe apple scab seasons.  As of today, June 19, we have had eight apple scab infection periods and have had several of those infection periods last for more than 36 hours and two of them lasting more than 48 hours. That has made it nearly impossible to control primary scab outbreaks.  With that being the case, we are at a point of now having to protect fruit from secondary scab.

Fig. 1

Season-long control is difficult if primary infections develop, like those in Fig. 1, which produce secondary inoculum placing fruit at risk for secondary, conidial infections.   With primary ascospores possibly depleted, we will have to continue to monitor scab infection events and maintain spray coverage accordingly for at least two more weeks, if not longer, since we have found primary lesions, like those in Fig. 2 on McIntosh and McIntosh hybrids like Cortland and Empire.  If you have seen lesions like those in Fig. 2, on your trees, then you will need to protect your fruit from secondary lesions.

Fig. 2

The best product for protecting your fruit is Captan, a protectant, so that means that your trees will need to be sprayed with Captan at the full labelled rate prior to any rain event to protect your fruit.  If there are no rain events between sprays, a single protectant spray will last at least 10 days but not more than 14 days, based on the product's labeled directions.  You will need to make sure that your trees and fruit are protected prior to any rain event if when using only a protectant. But, a protectant can lose its effectivness after 2" of rain, so you also want to keep an eradicant on hand like myclobutanil, which is available as Spectracide Immunox. A protectant like Captan has to be applied prior to a rain event.  If no protection is available during the wetting event, then only an eradicant like Immunox can be applied that has a reach back of at least 48 hours.  That means that it can still have an effect on the scab pathogen for up to 48 hours after a wetting event. A good option is to actually use both a protectant and an erdicant at the same time, like Captan mixed with Immunox, which will give you both protection and eradicant action after a wetting event. 

As always, be sure to follow the label directions on any spray product you may use.   For further information on control of apple scab, refer to:

 http://royaloakfarmorchard.blogspot.com/2018/04/apple-scab-season-approaches.html

Codling Moth Egg Hatch and NEWA

Our monitoring of codling moth (CM) continues as we approached egg hatch.   Eggs usually begin to hatch about 220 DD after the first catch, and catches of adults in pheromone traps should be increasing as the weekend approaches.  We applied our first CM spray on Tuesday and Wednesday nights at around 210 to 225 DD to get any eggs that had been laid covered. As we view our new NEWA Codling Moth Data Results, we will hit that 250 DD mark tonight.  

Royal Oak Farm Orchard Codling Moth Data for June 6, 2018

NEWA Rainwise Weather Station

NEWA, the Network for Environment and Weather Applications, is a weather network, making it possible for farmers to share resources for weather data collection, analysis, distribution, and archiving.  Weather stations, primarily located on orchards and farms, deliver data to the NEWA website, which automatically calculates and displays weather data summaries, crop production tools, and IPM forecasts for each individual orchard or farm where the orchard or farm has a NEWA weather station located.  Royal Oak Farm Orchard is also a member of the Apple Talk Network of growers and IPM Specialists throughout Northern Illinois, Wisconsin, Eastern Iowa and Southeastern Minnesota.

  

You can now apply the first codling moth spray at this time and up through roughly 350 DD to prevent larvae from entering the fruit. Because insecticide residues last 7 to 10 days and moths are continuously present throughout the summer, apply a spray every 7 to 10 days to prevent later broods of codling moth larvae from entering apple and pear fruits. Always follow the label directions of any spray you may use.

Several insecticides can be used for codling moth control including acetmaprid and/or spinosad.  Acetamiprid is a soft, conventional control and is available as  Ortho Flower, Fruit & Vegetable Insect Killer.  This is a ready to use product that contains .006% acetamiprid, and is also available in a concentrate containing .5% acetamiprid, a synthetic organic compound of the family of chemicals that acts as neonicotinoid insecticides. Acetamiprid is a contact, translaminar insecticide for sucking-type insects and can be applied as a foliar spray. Translaminar insecticides are absorbed by leaves and can move through the leaf to the opposite surface they contact. They are not truly systemic and do not move throughout the plant. Acetamiprid acts on a broad spectrum of insects, including aphids, thrips, plum curculio, apple maggot and Lepidoptera, especially codling moth.  When sprayed in the evening at sunset, it will not harm bees or other beneficial insects. Be sure to follow all label directions on the bottle for proper application.

An all natural approach is available in the form of Bonide’s Captain Jack’s Dead Bug Brew.  Captain Jack's Deadbug Brew® contains Spinosad (spin-OH-sid), a product first isolated from a naturally occurring soil dwelling bacterium that was collected on a Caribbean island from an abandoned rum distillery. Deadbug Brew® kills bagworms, borers, beetles, caterpillars, codling moth, gypsy moth, loopers, leaf miners, spider mites, tent caterpillars, thrips and more! Use on fruits, vegetables, berries, citrus, grapes, nuts and ornamentals and approved for organic gardening.

For additional information, see the following fact sheets which are available from local university extension services:

https://ecommons.cornell.edu/bitstream/handle/1813/43086/codling-moth-FS-NYSIPM.pdf

http://extension.psu.edu/plants/tree-fruit/insects-mites/factsheets/codling-moth