1. Insect
  2. Nut Crops
  3. Chestnut Pests

Chestnut-Filbertworm

  • Facebook logo
Image related to Chestnut-Filbertworm
Filbertworm
Melissopus latiferreanus Walsingham
Immature
© Ken Gray Insect Image Collection
Image related to Chestnut-Filbertworm
Filbertworm
Melissopus latiferreanus Walsingham
Adult
© Ken Gray Insect Image Collection
Image related to Chestnut-Filbertworm
Filbertworm
Melissopus latiferreanus Walsingham
Immature showing damage
© Ken Gray Insect Image Collection

Cydia latiferreana

Pest description and crop damage Adult moths have a wingspread of about 0.5 inch. Moths are gray to reddish with golden bands across each forewing. When mature, larvae are whitish with a translucent, amber-color head, 0.5 inch long. The larvae feed within the nut and destroy the kernel.

Biology and life history Filbertworm overwinter as larvae in silken cocoons, which may be found under leaves and leaf litter on the ground, or in cracks and crevices in bark. Some larvae also overwinter 1 to 2 inches beneath the soil surface. The larvae pupate, then the adults emerge beginning in mid-June, however, in recent years moths have emerged as early as mid-May. Moth emergence continues through October. After emergence, the adults find mates and lay eggs singly near developing nuts. Eggs mature in 8 to 10 days, and the larvae then move about in search of a nut to feed on. They burrow into the nut, feed on the kernel for 2 to 4 weeks, and bore their way back out. Most form cocoons to overwinter, although there may be a partial second generation.

Scouting and thresholds Pheromone traps are used to time sprays for this pest. Traps should be placed in the upper 1/3 of the canopy by mid to late May to capture early flight. Hang 4 traps for the first 10 acres (or 1 trap/2.5 acre) and one for each additional 4 acres. Take action if you find more than 5 moths in any one trap or 2-3 moths/trap/week. A degree-day model is available on uspest.org.

Management-biological control

Predators and parasitic wasps help by killing eggs and larvae before they cause damage. Trichogramma minutum is an egg parasitoid that attacks eggs of filbertworm and is produced by commercial insectaries. In order to implement supplemental biological control with Trichogramma, it is important to verify emergence of wasps from their container and make sure that the timing is aligned so that wasps are deployed at the same time filbertworm eggs are present in the orchard. Some moths are killed by predators such as bats. Bats capture moths on the wing during dawn and dusk flight periods. The activity of biological control from insect natural enemies will be affected by management tactics for other pests. For example, reliance on mating disruption against key pests has been shown to enhance biological control in orchards because it can reduce insecticide use.

Management-cultural control

First nut drop typically contains a higher percentage of nuts infested by filbertworm. Flailing these first nuts prior to harvest may reduce infestation levels. Flailing acorns from oaks near the orchard may also help reduce filbertworm pressure. Some growers have had success running pigs through their orchard or adjacent oak groves after harvest to feed on fallen, larvae-infested nuts.

Management-chemical control: HOME USE

  • azadirachtin (neem oil) (Azera)-Some formulations are OMRI-listed for organic use.
  • boscalid (often as mix with other chemicals) (Bonide Fruit Tree & Plant Guard)
  • carbaryl (GardenTech Sevin Concentrate Insect Killer)-Do not apply to blooming trees or weeds or cover crops in bloom. Deadly to bees. Apply early July and again 3 weeks later.
  • gamma cyhalothrin (Spectracide)
  • kaolin clay-Strong suppression effect. OMRI approved for organic use. 4-hour reentry. Apply prior to egg laying (815 DD), maintain coverage throughout flight period. Good agitation in spray tank is essential.
  • lambda-cyhalothrin (often as mix with other chemicals) (Bonide Fruit Tree & Plant Guard)
  • pyrethrins (often as mix with other chemicals) (Azera)-Some formulations are OMRI-listed for organic use.
  • spinosad-Some formulations are OMRI-listed for organic use. Apply at or just prior to egg hatch to target emergent larvae
  • zeta-cypermethrin (GardenTech Sevin Insect Killer)

Management-chemical control: COMMERCIAL

Pheromone trapping is encouraged for accurate spray timing.

  • acetamiprid (Assail 70WP) at 2.3 to 4.1 oz/A (0.10 to 0.18 lb ai/A). PHI 14 days. No more than 4 applications per season.
  • alpha-cypermethrin (Fastac CS) at 3.2 to 3.8 fl oz/A (0.021 to 0.025 lb ai/A). PHI 7 days. REI 12 hr. Do not exceed 11.4 fl oz/A per season. Highly toxic to bees, extremely toxic to fish and aquatic invertebrates. Do not apply within 25 feet of aquatic habitats, or with 150 ft if aerial application. Apply as indicated by scouting.
  • beta-cyfluthrin (Baythroid XL) at 2.0 to 2.4 fl oz/A or 0.016 to 0.19 lb ai/A. Maximum per 14 day and per season: 0.022 lb ai/A. PHI 14 days.
  • beta-cyfluthrin + imidacloprid (Leverage 360) at 2.8 fl oz/A (0.022 lb ai/A). Maximum 2.8 fl oz/A per year. PHI 14 days.
  • bifenthrin-
    • Brigade WSB at 0.05 to 0.2 lb ai/A. PHI 7 days. REI 12 hr. Do not graze livestock on treated cover crops. Highly toxic to bees and toxic to fish and aquatic invertebrates.
    • Fanfare EC at 3.2 to 12.8 fl oz/A (0.05 to 0.20 lb ai/A). PHI 7 days. Do not graze livestock on treated cover crops. Highly toxic to bees and toxic to fish and aquatic invertebrates. WA only.
  • carbaryl (Sevin XLR Plus or its equivalent in another formulation) at 0.5 to 1.25 quarts/100 gal water (2 to 5 quarts/A). PHI 14 days. REI 12 hr. May cause rapid increase of aphid populations 3 to 4 weeks after application. Extremely toxic to aquatic invertebrates.
  • chlorantraniliprole (Altacor) at 3 to 4.5 oz/A. PHI 10 days. REI 4 hr.
  • Chromobacterium subtsugae strain PRAA4 (Grandevo) at 1 to 3 lb/A. OMRI-listed for organic production.
  • diflubenzuron (Dimilin 2L) at 16 fl oz/A. Most effective if applied before egg-laying. Extremely toxic to aquatic invertebrates. Do not apply within 25 ft of bodies of water. Do not make more than 4 applications per season. PHI 28 days. REI 12 hr.
  • emamectin benzoate (Proclaim) at 3.2 to 4.8 oz/A. PHI 14 days.
  • esfenvalerate (Asana XL) at 8 to 10 fl oz/100 gal water (9.6 to 19.2 fl oz/A or 0.05 to 0.1 lb ai/A). PHI 21 days. REI 12 hr. Do not apply more than 0.2 lb ai/A per season. Extremely toxic to fish and aquatic habitat.
  • lambda-cyhalothrin (Warrior II) at 2.56 to 5.12 fl oz/A. PHI 14 days. REI 24 hr. Do not exceed 0.16 lb ai/A per season or 0.12 lb ai post bloom.
  • methoxyfenozide (Intrepid 2F) at 8 to 16 fl oz/A. PHI 14 days. REI 4 hr. Apply when egg hatch begins. Reapply at 14- to 21-day intervals under high pressure or sustained moth flight. Do not exceed 24 fl oz/A per application or 64 fl oz/A (1 lb ai/A) per season. Do not apply within 25 ft of an aquatic habitat, 150 ft if applied by air.
  • methoxyfenozide + spinetoram (Intrepid Edge) at 6 to 12 oz/A. Apply at initiation of egg hatch, if necessary, reapply after 14 -21 days, but not before 14 days. PHI 7 days. REI 4 hr. No more than 12 fl oz/A/season.
  • permethrin-
    • Ambush 25W at 12.8 to 25.6 oz/A. PHI 14 days. Do not graze treated orchards. Extremely toxic to fish and aquatic habitat.
    • Ambush at 0.2 to 0.4 lb ai/A. PHI 14 days. REI 12 hr. Do not graze treated orchards. Extremely toxic to fish and aquatic habitat.
    • Pounce 3.2 EC at 8 to 16 oz/A. PHI 14 days. REI 12 hr. Do not graze treated orchards. Extremely toxic to fish and aquatic habitat.
  • pyriproxyfen (Esteem 35 WP) at 4 to 5 oz/A. Do not apply more than twice per season. PHI 21 days. REI 12 hr.
  • spinetoram (Delegate WG) at 1.5 to 1.75 oz/100 gal water (4.5 to 7 oz/A). PHI 14 days. Apply no less than one week apart, with a maximum 4 applications per season.
  • spinosad (Entrust SC, Success Naturalyte) at 4 to 10 oz/A (0.06 to 0.16 lb ai/A). PHI 1 days. REI 4 hr. Entrust SC OMRI-listed for organic use. REI 4 hr. Do not exceed 29 oz/A (0.45 lb spinosad) per season.