July 8, AppleTalk Call Summary

AppleTalk Conference Call Summary
Tuesday, July 8th, 2014, 8:00 – 9:00 a.m.
Presenter: John Aue, Threshold IPM.
Moderator: Peter Werts, IPM Institute of North America; questions or comments, pwerts@ipminstitute.org

July 8th Call download: Click Here

Apple maggot minute 1:10
Treatment practices for apple maggot can include spot spraying, e.g., borders and attractive varieties, and alternate-row-middle applications. Consider applying traps to differentiate pressure between spray tanks: 20 (total acres) / 5 (acres per spray tank) = 4 monitoring blocks. A block of attractive varieties, e.g., Redfree or Yellow Transparent, in the middle of a large block may require every row to be sprayed. In majority of situations a full cover application is not necessary for effective control. Use trap data to make management decisions. Refer to July 1 AppleTalk for trapping guidelines.

Codling moth 6:40
Damage from codling moth larvae is becoming visible. While scouting differentiate between larvae that suffered mortality and ones that are alive in the fruit; alive larvae will result in greater pressure during second generation. This information is also useful in determining where gaps existed in pesticide coverage and timing. If trap counts increase, or a large flight is experienced, a “biofix” can be set to determine a pesticides efficacy in controlling hatching larvae (ten to fourteen days from flight). Note: materials for codling moth only control larvae.

San Jose scale 12:10
San Jose scale crawlers are entering the white cap stage. Orange to yellow crawlers enter the white cap stage when they excrete a protective layer of wax, turning white. If crawlers have not been noticed, continue to monitor tapes set on scaffold limbs for activity. If none were noticed in the past two to three weeks it may suggest an application was not necessary. If crawlers have shown on tape and a material was not applied, continue to monitor tape and also look for crawlers accumulating at the calyx and stem end of fruit. If the majority of scale are in the crawler stage applying a pesticide is likely to provide control. If the majority is in the white cap stage an application will be unsuccessful. Second generation will emerge in August.

Apple rust mite 19:15
Apple rust mites are a common secondary pest that require high populations to cause damage; current threshold is 200 mites per leaf. Damage can be observed as an olive drab color on the underside of leaves. Populations will continue to grow once the terminals have set. Not much of a concern on large established trees, yet can be harmful on young trees. While scouting, turn over growing shoots and look for discoloration and scan leaf surface with hand lens to see if mites are present (requires 10x or greater magnification). These mites are an important food source for numerous predatory arthropods.

Two-spotted spider mite 23:45
Two-spotted spider mites (TSSM) have a wide range of native host plants which includes broadleaves and red clover. In dry years, TSSM may feed on tree foliage and can be as destructive as European red mites (ERM). Damaging levels will be observed first near the trunk; where they travel into the tree. Damage can be observed as light green or whitish areas along the midrib. Must use 10x magnification to see the two spots; are more difficult to identify then ERM.

European red mite 27:45
While scouting it is important to differentiate between thresholds and physical damage. Thresholds are based on population densities and increase through the season, i.e., June, 2.5 mites/leaf; July, 5 mites/ leaf; August, 7.5 mites/leaf. Although sampling can provide an accurate read on a population it does not always reflect actual pressure. Visible damage can be present although populations are under threshold. Damage may be a result of length of feeding. The mite day equation can be used in this scenario: 1 (mite per leaf) x 30 (days of feeding) = 30 Mite Days. If physical damage is observed, it is time to apply a material. After significant bronzing develops it is too late to apply a material; mite population will decrease naturally from starvation. In most years, beneficial insects control this species.

Mite predator complex 35:15
Predatory arthropods that prey on adult mites, egg and larvae, include minute pirate bugs, black hunter thrips and many species of predatory mites.

Miticide 37:00
If bronzing is developing but thresholds are not exceeded materials, i.e., Apollo (clofentezine), Savey (hexythiazox) and Zeal (etoxazole), which work on eggs and nymphs will provide control. These products are not considered rescue materials and will take time to reduce populations. When populations are high and a lot of damage is present use products regarded as rescue materials, such as, Envidor (spirodiclofen), Nexter (pyridaben) or Portal (fenpyroximate).

Obliquebanded leafroller 39:10
Small obliquebanded leafroller (OBLR) larvae can be found in developing terminals. Larvae are small green worms with caramel to black head capsules. These worms are offspring from the first flight of OBLR this season. Worms at petal fall and first cover are overwintering larvae from last year’s second generation flight. In addition to feeding on foliage, larvae will also feed on fruit and are capable of causing economic damage in some years. There is no threshold for pheromone traps, but if monitor growing points threshold is an infestation of three percent of terminals. Scout fruit if cultivars have set terminals. Damage will be on the surface of the apple and at harvest will be difficult to distinguish from our lepidoptera. Large flights now is a result of the overwintering generation not being controlled; may result in high population for second generation. Products for codling moth and other internal worms are effective on OBLR; Bt offers exceptional control. Do not exceed seasonal application rates. Note: OBLR are resistant to organophosphate materials in Michigan and Washington.

Dogwood borer 55:20
Dogwood borer traps can still be set in orchards. Trap counts will provide information on hatching larvae in a few weeks.

Japanese beetle 55:45
Small numbers of Japanese beetle so far, please contact John or Peter if you have significant populations.

Additional articles and resources
• Glufosinate products, sold as Rely 280, Cheetah and other trade names. Plant and Pest Advisory. Rutgers Cooperative Extension. June 27, 2014.