Apple Maggot & the Mid-Season Lep. Complex: July 5th

The first flight of apple maggot (AM) has not yet been observed at the Hudson Valley Research Lab (HVRL). With recent rains (0.8″ since July 1st) emergence should be on the near horizon. Traps for AM should be placed in early maturing and more susceptible fruit such as Ginger Gold, to monitor the insect over the coming weeks. The trap and lure will provide best timing, using a 5 fly per trap threshold, to begin and maintain AM management for the remainder of the season.

At this point in the season we are nearing the end of obliquebanded leafroller (OBLR) emergence.

The majority of 1st instar nymphs have hatched from egg clusters and are now developing into larger larva. In untreated apple, foliage and fruit feeding will become more evident over the course of the week.

In orchards with historic OBLR damage, growers controlled the larval emergence this season beginning in early to mid-June, making two applications for the summer generation at 14 to 21 day intervals.

Approximately 90% OBLR hatch occurred @ 810 DD43 (23rd June) with 1035.7 DD43 accumulations as of July 2nd in Highland, representing nearly 100% hatch. The residual of two applications during hatch using effective insecticides have been shown to reduce the OBLR through emergence. With relatively little in the way of rainfall this season , residual activity should have been excellent.

Codling moth; Order Lepidoptera, Family Tortricidae (CM): The end of the first generation CM is at hand with low trap captures observed over the past week. The model to predict the 2nd generation of codling moth management uses 1260 DD (base 50°F) after 1st generation biofix (on May 25, HVRL) to determine timing for 1st larval hatch. Management will include a follow-up application 2 weeks later. The 2nd generation of codling moth are predicted to emerge in mid-July in Highland depending on temperature over the next two weeks. We’ll kep you updated on CM emergence next week.

To determine the presence of CM in your orchard hang 1 trap per 10 acre orchard block at the top of the canopy, in blocks where historic internal lep. damage has occurred.

Cornell suggested trap threshold for CM: If > 5 codling moths are caught per trap per week using standard lures, there can be problems in fruit from the next generation.

High trap counts are a warning to prepare for management. If trap counts continue to exceed threshold throughout the season, maintaining insecticide coverage on a 2 week interval should be strongly considered.

When scouting for fruit injured from this pest during the 1st generation, which began in early June, look for a red bulls eye with a entry hole, red ringed holes along the cheek and shoulder likely to contain frass, or frass present in the calyx end of the fruit. San Jose scale also produce a red ring from feeding, however, there will be no hole or frass from SJS fruit feeding. Instead, the developing scale insect will be easily wiped off when rubbed, leaving a white dot at the center.

If you cut open CM injured fruit, you are likely to find the seed fed upon. Core feeding from lesser apple worm and Oriental fruit worm will not result in seed feeding. Management for this level and stage of damage is ineffective and can not be controlled now. If populations of CM reside within the orchard or if adults migrate in from abandoned trees along the borders, they are likely to give rise to damaging populations beginning mid-July at the onset of 2nd CM generation.

Trapping in your orchard is the best way to determine presence of the insect.

Generally, we are seeing very high incidence of CM injury in untreated and organic treated fruit this season AND we have heard from New England growers regarding increased fruit injury from internal worms over the past few years.

Since apple maggot is not yet at threshold in high pressure blocks, the selection of management tools to control both codling moth and apple maggot should be considered for use next week to ten days out. A number of options are very effective against both insects.

Assail used only for CM management can be used effectively at lower rates (4-8 oz./A). However, for AM management, rates should be at the 8.0 oz./A. Restrictions for Assail include:

• Do not make more than 4 applications per season.
• Do not apply more than once every 12 days.
• Do not apply less than 7 days before harvest (PHI = 7 days).
• Do not exceed a total of 0.60 lbs. active ingredient (32.0 ozs. product) per acre
per growing season.

Imidan (Phosmet) is also very effective against both insects at 2 1/8 to 5 3/4 lbs/A.

The pyrethroid group and pre-mix formulations with a pyrethroid will also perform well against this complex.

Given the drought conditions over the past several weeks, some farms in the mid-Hudson Valley, including Highland, Milton and Marlboro, may consider managing the stink bug complex, including the Brown Marmorated Stink Bug (BMSB). As we have seen few BMSB to date, its likely the native complex of green sting bug, moving from woodlands or the brown stink bug from broad leaf hosts as they dry down would move to irrigated apple. Danitol has been a good choice in these situations as it also controls AM and CM. However, as we move toward August, BMSB has often been the culprit of damage to fruit near harvest, in which case a pre-mix or Bifenthrin to manage this additional pest should be considered as 10 adult per BMSB trap reaches threshold indicated on EDDMaps/BMSB.

BMSB tools for control can be found here.