On a Roll: Obliquebanded Leafroller Emergence. June 18th

Brief: We have been seeing obliquebanded leafroller, Choristoneura rosaceana (OBLR) adult flight since Monday, June 3rd, in Highland, Milton and Walden, NY. Egg laying is continuing in earnest. Based on NOAA weather forecasts, the predicted emergence date for the 1st generation OBLR larva is the 18th of June.

In orchards that have had a past history of severe OBLR fruit damage or if populations of overwintering larvae were high, apply protective applications. The first management application should be timed to coincide with the first hatch of larvae at approximately 350 DD base 43F after biofix followed by a second spray 10-14 days later.

OBLR Pheromone Trap

OBLR Pheromone Trap

Obliquebanded Leafroller (OBLR) is native to the continental US and widely distributed in North America. East Coast populations have caused considerable injury to tree fruit with OBLR larvae feeding on a wide range of preferred hosts in the plant family Rosaceae. Hosts include stone and pome fruit with feedng also observed in fruiting bushes such as blueberry and woody ornamentals, hawthorn, alder, and ornamental roses.

Two adult generations of OBLR can be observed yearly. Spring flight of the OBLR adult begins about three to four weeks after petal fall, continuing for three to four weeks.

Adults lay Egg masses, containing a few hundred eggs, are laid on the upper surface of leaves. Eggs hatch after 10-12 days. The larvae feed on floral parts, developing fruits and young leaves, folding leaves for shelter. There are 6 larval stages. At pupation the larva spins a cocoon attached to the leaf.

OBLR overwinters in the third larval stage and they start feeding on floral parts and developing fruit in Spring. The first summer generation of larvae feeds on more mature fruits causing significant damage.If we capture them over two to three successive days (sustained flight) we will establish the biofix date and begin calculating heat accumulations using 45DD to help us determine, using the NEWA model, the early period of emergence for optimum timing of insecticide applications. If you find OBLR in your traps prior to or after our trap findings you can use the NEWA site to fine tune your application window.

Over the past ten years, growers have been able to control OBLR larva through the use of effective insecticide programs targeting three periods of larval activity. These include:
* Employ applications against the overwintering generation during either the pre-bloom / bloom or petal fall periods
* Use 1-2 applications against the summer generation
* In high population years target 1 application against late summer generation.

For the three periods of management we recommend using two or three distinct yet very effective active ingredient groups or IRAC classes. In this way we hope to reduce the resistance potential of the insect over time.

Late season fruit feeding Fruit injury caused by second brood obliquebanded leafroller larvae

Late season fruit feeding Fruit injury caused by second brood obliquebanded leafroller larvae

The classes used against the leafrollers with highest degree of efficacy include:
Entrust 2SC, 80WP (spinosad) (IRAC Class 5), have been used successfully against the leafroller surface feeding and internal Lep. complex.
Delegate (spinetoram) (IRAC Class 5), is a broad spectrum synthetic modification of spinosad against leafroller and internal Lep. complex. The placement for these materials has been predominately at the onset of hatch of the summer generation larva of OBLR, providing excellent results in NY State.
Proclaim (emamectin benzoate) (IRAC 6), a second-generation avermectin insecticide related to Agri-Mek, is also an excellent insecticide against the OBLR while having a low impact on beneficial mites.
Bt products such as Biobit, Dipel, Javelin, and MVP (IRAC 11 B2) also have a low impact on beneficial mite and are very effective against OBLR.
Intrepid (methoxyfen-ozide) (IRAC 18A) another reduced risk insecticide very effective against the larva, imitates the natural insect molting hormone and works by initiating the molting process. Intrepid is quite safe to birds, fish, and most beneficial insects.
Altacor (chlorantraniliprole) (IRAC Class 28) is a anthranilic diamides, which activate the insect’s ryanodine receptors, stimulating release of calcium from muscle tissues, and causing paralysis and death, controls of a range of insect pests in pome and stone fruits. These include codling moth, oriental fruit moth, and obliquebanded leafroller, green fruitworm, spotted tentiform leafminer, apple sawfly, European corn borer, and suppression of apple maggot, cherry fruit fly, white apple leafhopper, and plum curculio. It has low toxicity to bees, beneficial mites, birds, fish and mammals. Not registered for use in Kings, Queens, Nassau, or Suffolk Counties.
Exirel (Cyantraniliprole ) (IRAC Class 28) is also a 2nd-generation anthranilic diamide. Like Altacor, Exirel is labeled for the control of a range of insect pests in pome and stone fruits, including codling moth, oriental fruit moth, and obliquebanded leafroller. Other species listed on the label include green fruitworm, spotted tentiform leafminer, European apple sawfly, white apple leafhopper, cherry fruit fly, spotted wing drosophila, and Japanese beetle, with activity against pear psylla and plum curculio, and suppression of apple maggot. It has high toxicity to bees, but low toxicity to birds, fish and mammals.

Premix Insecticides:
Besiege (Chlorantraniliprole/Lambda-cyhalothrin) (IRAC Class 28 & 3), pome fruit label includes internal worms and leafrollers, aphids, (excluding woolly apple aphid), apple maggot and cherry fruit fly adults, leafhoppers, leafminers, plum curculio, Japanese beetle, pear psylla, plant bugs, stink bugs, and other caterpillars.
Voliam Flexi (Chlorantraniliprole/Thiamethoxam) (IRAC Class 28 & 4A) is effective against a range of pests in pome and stone fruits in NYS. This product is a mixture of thiamethoxam, the a.i. of Actara, and chlorantraniliprole, the a.i. found in *†Altacor and *†Voliam Xpress. The label lists lepidopteran pests such as codling moth and oriental fruit moth, obliquebanded leafroller, leafminers and green fruitworm; plum curculio; European apple sawfly; leafhoppers and aphids (except woolly apple aphid); pear psylla; plus (in stone fruits only) cherry fruit fly, stink bugs, tarnished plant bug and thrips.
Minecto Pro (Cyantraniliprole/Abamectin) (IRAC Class 28 & 6) is a pre-mix combination of cyantraniliprole and abamectin, labeled for pome fruit and stone fruit use in NY to control Lepidoptera species and mite when used with a penetrant. It is a restricted use pesticide with a high bee-poisoning hazard; not registered for use in Nassau or Suffolk counties.

Since the development of insecticide resistance is dependent on the volume and frequency of applications of insecticides and the inherent characteristics of the insect species, we should limit one insecticide class to a single generation of pest for resistance management purposes. The present model for insecticide resistance management (IRM) practices then is to use a single insecticide class for a single generation of insect pest.

For example, an IRM program against the lepidopteran complex, specifically OBLR, would use effective insecticides listed above (X, Y, Z) in three different IRAC classes (A, B, C) throughout the season.

Insecticide X (Class A) 1 application @ TC-P or PF for overwintering OBLR
Insecticide Y (Class B) 2 applications @ 14d; first emergence of 1st brood OBLR larva
Insecticide Z (Class C) 1 application @ first emergence of 2nd brood OBLR larva if needed.

Given the historic failures the apple industry has experienced managing the leafroller and internal worm complex, we should consider designing programs to maintain the effectiveness of these excellent IPM tools beginning early in the season, before the heat of the battle begins.