1. Insect
  2. Nut Crops
  3. Hazelnut Pests

Hazelnut-Filbertworm

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

Cydia latiferreana

Pest description and crop damage Filbertworm is the key pest of hazelnuts in the Pacific Northwest and a close relative of codling moth, one of the most economically important insects worldwide. Adult moths are gray to reddish with golden bands across each forewing. Female moths lay the eggs on the upper surface of leaves. Recent research suggests that the larvae can subsist on leaves alone and they may damage early developing nut clusters before the nuts are big enough to physically infest. This can cause nuts or nut clusters to abort, which represents potential yield loss for the grower. However, the major concern is infestation of nuts, which is a major cause for dockage from nut processors. Larvae infest nuts and destroy the kernel, leaving only mold and frass. When fully developed, the larvae are whitish with a brown head capsule and are approximately 0.5 inch long. Research has shown that shell thickness at the basal scar/micropyle can affect susceptibility of different hazelnut cultivars to this pest. Trees are attacked by moths up to and beyond harvest, but nut susceptibility to attack by larvae can decline as shells fully harden.

Biology and life history The insect is found in several wild and cultivated nuts (see Chestnuts-Filbertworm) in North America but is particularly common in acorns and hazelnuts in the Pacific Northwest. The filbertworm overwinters as a larva in a silken cocoon (hibernaculum) under leaves and debris on the ground or in cracks and crevices on trees. Some larvae also overwinter 1-2 inches beneath the soil surface. The larvae pupate in spring and the adults begin to emerge and get caught in traps in early June through October. After mating, the female moths begin to lay single eggs on leaves. Eggs hatch in 8 to 10 days, and the tiny larvae search out nut clusters. They attack developing clusters and later burrow into the nuts, entering the shell through the micropyle, the pore in the center of the basal scar. Larvae feed on the kernel for 2 to 4 weeks. Mature larvae typically chew a larger exit hole through the side wall of the shell. After a period of wandering, larvae form cocoons (hibernaculae) to overwinter. Ideally, sprays are timed to target the eggs and the wandering larvae before they penetrate the nuts. Some materials will also kill adult moths and it is important to understand this when following trap captures. Only materials with adult activity (such as pyrethroids) will cause shutdown of pheromone trap captures. More selective sprays target the immature stages and will not shut down trap captures because they are less toxic to adult moths. However, the residue from such materials will continue to protect nuts from attack even as moths are caught in traps and are laying new eggs. Proper timing of spray applications is critical with selective materials and those with lower residual activity.

Pest monitoring Use of pheromone traps is recommended for timing management. Filbertworm flight has been starting earlier in the season compared to historic norms. Previous recommendations were to start hanging pheromone traps before the flight of filbertworm moths begins in mid-June, but now it is clear that traps should be placed by mid- to late May to capture the first moths in early June. Note that early moth captures can indicate potential for damage to developing nut clusters resulting in aborted nuts or clusters. Use 4 traps for the first 10 acres (or 1 trap per 2.5 acre) and one for each additional 4 acres. Lower densities of traps can be used successfully, but this may increase the likelihood of going over the threshold. Place the traps in the upper third of the canopy; moth captures will not be representative if traps are not placed high in the canopy (pheromone is heavier than air). Keep extra lures in the freezer (not in your vehicle), and replace lures and trap liners according to the recommendations of the manufacturer (dirty liners won't catch moths). The action threshold is an average of 2 to 3 moths per trap per week, or 5 moths in any one trap. Apply selective larvicidal insecticides 8 to 12 days after reaching the threshold in your orchard block to target larvae emerging from eggs and wandering on the tree. This delay reflects the time required for moths to mate and for females to mature fertilized eggs and for eggs to begin hatching. Products with long residuals can be applied soon after trap captures go above threshold. Products with ovicidal activity (kills eggs) can be applied several days after going over the threshold because ovicides are most active when eggs are laid on top of residues. However, oils can be applied over the top of eggs to smother them and these should be applied prior to egg hatch 8 to 12 days after threshold is reached. A second cover spray may be necessary in 2-3 weeks, or later in the season if moths continue to be caught in traps at rates above the threshold and the residual activity of the first application is expired. Moths flying late in the season can cause unexpected crop damage, so it is important to keep monitoring traps and using trap capture action thresholds through nut drop. If the trap threshold is not reached, then sprays are not necessary.

Management-biological control

Predators and parasitic wasps likely assist in killing some eggs and larvae before they gain entry to the nuts. Some moths may also be killed by predators. Bats may capture moths on the wing during dawn and dusk flight periods. The activity of biological control will be affected by management tactics for other pests. For example, use of mating disruption against key pests has been shown to enhance biological control in orchards.

Management-cultural control

Hazelnut varieties are not equally susceptible to filbertworm. The thickness of the micropyle, which is the thinnest point of the shell on the basal scar of the nut determines susceptibility, as this is the point of entry for the newly hatched larvae into the nut. Hardness of the shell can also affect susceptibility later in the season. Of the hazelnut cultivars currently planted, Yamhill was found to have the thinnest average shell at the micropyle. McDonald, Wepster, Sacajawea, and PollyO had very similar shell thickness at the micropyle but thicker than Yamhill. Lewis, Jefferson, Dorris, and Barcelona had the thickest shell at the micropyle.

First nut drop typically contains a higher percentage of nuts infested by filbertworm. Flailing or otherwise destroying these first nuts prior to harvest may reduce infestation levels. Flailing acorns from oaks near the orchard may also help reduce filbertworm pressure.

Management-behavioral control

Isomate FBW Ring is a commercial mating disruption product. Apply a minimum 20 dispensers per acre (more point sources may enhance the effect). Hang pheromone dispensers high in the canopy on lateral branches before initial moth flight. Continue to monitor traps and prepare to apply border sprays or supplemental cover sprays if traps capture moths at rates above the threshold. Large, contiguous blocks are most conducive to mating disruption. The continual release of pheromone from dispensers in the orchard interferes with the male moth's ability to locate females for mating within the orchard. Mated females originating from outside the orchard can still come in and lay eggs resulting in damaged nuts. Mating disruption technology is best applied to low to moderate filbertworm populations, so consider getting any problematic moth populations under control before utilizing mating disruption. Do not apply to home orchards, orchards with steep slopes, or orchards with a high edge to core ratio.

Management-chemical control: HOME USE

  • acetamiprid-PHI 14 days. No more than 4 applications per season.
  • azadirachtin (as a mix with other ingredients)-Some formulations are OMRI-listed for organic use.
  • bifenthrin (often as a mix with other ingredients)
  • carbaryl
  • esfenvalerate
  • gamma cyhalothrin (as a mix with other ingredients).
  • spinosad-Some formulations are OMRI-listed for organic use.
  • zeta-cypermethrin (often as a mix with other ingredients)

Management-chemical control: COMMERCIAL USE

Filbertworm emergence notices are sent to growers.

  • acetamiprid (Assail 70WP) at 0.57 to 1 oz/100 gal water (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 ia/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 (Bathyroid) at 2 to 2.4 oz/A (0.016 to 0.019 lb ai/A). PHI 14 days. REI 12 hr.
  • 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)-See label for specific formulations as some concentrations vary. Seven XLR plus 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 2.5 to 4.5 oz/A (0.055 to 0.99 lb ai/A). PHI 10 days. REI 4 hr. Make initial application just before or at filbertworm egg hatch. Depending on the length of the filbertworm moth flight, multiple applications may be required to protect the crop. Under heavy filbertworm pressure, apply ALTACOR on a 14-day retreatment interval. With low to moderate filbertworm pressure, apply ALTACOR no longer than 21-day interval.
    • Vantacor at 1.4 to 2.5 oz/A. Make no more than 4 applications per year and do not reapply within 7 days. PHI 10 days. REI 4 hr.
  • cyfluthrin (Baythroid XL) at 2 to 2.4 oz/A (0.016 to 0.019 lb ai/A). PHI 14 days. REI 12 hr.
  • diflubenzuron (Dimilin 2L) at 12 to 16 fl oz/A. PHI 28 days. REI 12 hr. Extremely toxic to aquatic invertebrates. Do not apply within 25 ft of bodies of water.
  • emamectin benzoate (Proclaim) at 3.2 to 4.8 oz/A. PHI 14 days.
  • esfenvalerate (Asana XL) at 7.3 to 12.8 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.
  • fenpropathrin (Danitol 2.4 EC) at 10.3 to 21.3 oz/A (0.2 to 0.4 lb ai/A). PHI 3 days. REI 24 hr. At least 50 gal water for ground applications. Note buffer requirements for use near aquatic zones.
  • flubendiamide + buprofezin (Tourismo) 10 to 14 fl oz/A in a minimum of 100 gal water. Do not apply as alternate row middle (ARM) sprays; full cover sprays only. PHI 60 days. REI 12 hr.
  • GS-omega/kappa-Hxtx-Hv1a (Spear-Lep) at 1 to 2 pints/A. Biological insecticide that should be tank mixed with equal parts of Bt. PHI 0 day. REI 4 hr.
  • kaolin clay (Surround WP) at 50 to 75 lb/A. Suppression only, OMRI-listed for organic use. PHI 0 days. REI 4 hr.
  • lambda-cyhalothrin-
    • Warrior II/ Grizzly Too at 1.28 to 2.56 fl oz/A (0.02 to 0.04 lb ai/A). PHI 14 days. REI 24 hr. Do not exceed 0.16 lb ai/A per season or 0.12 lb ai post bloom.
    • LambdaStar/ Drexel L-C 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, generics) 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 2E at 0.8 to 1.6 pints/A. PHI 14 days. REI 12 hr. Do not graze treated orchards. Extremely toxic to fish and aquatic habitat.
    • Pounce 3.2 EC at 0.5 to 1 pint/A. PHI 14 days. REI 12 hr. Do not graze treated orchards. Extremely toxic to fish and aquatic habitat.
    • PermaStar AG at 8 to 16 oz/A. PHI 14 days. REI 12 hr. Highly toxic to bees, toxic to fish and aquatic invertebrates.
  • pyriproxyfen (Esteem 35 WP) at 3.2 to 4 oz/100 gal water (13 to 16 oz/A). Do not apply more than twice per season. PHI 21 day. REI 12 hr.
  • spinosyns-
    • 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) at 4 to 10 oz/A (0.06 to 0.16 lb ai/A). PHI 1 days. REI 4 hr. OMRI-listed for organic use.
    • spinosad (Success Naturalyte) at 4 to 10 oz/A in 100 gal water (0.06 to 0.16 lb ai/A). PHI 1 days. REI 4 hr. Do not exceed 29 oz/A per season. OMRI-listed for organic use.
  • tebufenozide (Confirm 2F) at up to 30 oz/A. PHI 14 days. REI 12 hr. Apply when egg hatch begins. Do not exceed 30 oz/A per application or 122 oz/A for the season.