Agriculture

Obliquebanded Leafroller

  • Choristoneura rosaceana
Updated: 10/2014

Tools

PestManage: a decision support tool to view and compare pest management options

Description of the Pest

Larvae of the obliquebanded leafroller are yellowish green caterpillars with a dark head capsule. When disturbed, they wiggle backwards and drop to lower leaves or to the ground on a silken thread. Larvae fold or roll leaves together to form protective shelters in which they feed. Adult moths have dark brown bands running at oblique angles across their wings. Obliquebanded leafroller overwinters as second-instar larvae under bark and in crevices of trees. There are three generations each year in the pistachio-growing areas of the state.

Damage

Obliquebanded leafroller larvae cause two types of damage to pistachios. When populations are high, leaves are tied together, which kills portions of leaves and reduces the overall photosynthetic capacity of the trees. The most important damage to the crop, however, is when larvae invade the clusters from June to August and feed on the peduncles (stems). This causes the peduncles to dry and shrivel, thus reducing crop yield.

Management

Spring treatments of young caterpillars with Bacillus thuringiensis or spinosad and monitoring with pheromone traps to time summer applications are the key approaches to monitoring this pest in pistachio.

Biological Control

There are several parasite species (Macrocentrus iridescens, Habrobracon gelechiae Bracon sp. and Goniozus sp.) that attack obliquebanded leafroller and can significantly reduce its populations in the second and third generations. None of these parasitoids are commercially available (the Goniozus species that attacks obliquebanded leafroller is not the same species (G. legneri) that attacks navel orangeworm.

Organically Acceptable Methods

Springtime sprays of Bacillus thuringiensis and summer spray of the Entrust formulation of spinosad are acceptable for use in an organically managed orchard.

Monitoring and Treatment Decisions

Degree-Days

Calculate degree-days for obliquebanded leafroller in your location.

Learn how to use degree-days to time insecticide applications.

Right after budbreak, start looking for obliquebanded leafroller strikes and leaf ties. Record observations for future pheromone trapping and management decisions.

To time summer treatments,

  1. Put out pheromone traps by late-April.
  2. Check traps twice per week to identify the biofix date.
  3. Continue to examine trees for leaf rolls, leaves tied together, and live larvae when traps indicate adults have emerged.
  4. When male moths are first found in traps (biofix), begin degree-day calculations (upper threshold 94°F, lower threshold 43°F).
  5. Treat when 800 degree-days have accumulated.

Pesticides and Natural Enemy Releases

Not all registered pesticides are listed. The following are ranked by their IPM value, with the most effective and least harmful to natural enemies, honey bees, and the environment listed at the top of the table. When choosing a pesticide, consider information related to water and air quality, resistance management, and the pesticide's properties and application timing. Use PestManage to compare summarized management options for different pests in the same crop. Always carefully read the label of the product being used and take all necessary precautions when handling pesticides.

Rank Active ingredient Example trade name Group Group Order MoA 1 Amount per acre REI (hours) ‡ PHI (days) ‡ Comments Selectivity 2 Bees 3 Predatory mites 4 Predators 5 Parasitoids 5 Residue duration 6 Leaching(fish) 7 Adsorbed runoff(fish) 8 Solution runoff(human) 9 Leaching(human) 10 Solution runoff(human) 11 Last updated 12
A
various products # Spring 4

11A

Label rates 4 0 Apply when trees are beginning to leaf o... narrow III low low low none — — — — — 10/2014
E
Brigade WSB Summer 5

3A

8–32 oz 12 7 Do not apply near aquatic areas. Brigade... broad I high high high long intermediate low extra high very low intermediate 10/2014
C
Altacor Summer 5

28

3–4.5 oz 4 10 — narrow III low low low/moderate short — — — — — 10/2014
D
Proclaim Summer 5

6

3.2–4.8 oz 12 14 Do not apply near aquatic areas. Proclai... narrow I — — — — high low high intermediate intermediate 10/2014
G
Danitol 2.4 EC Summer 5

3A

10.66–21.33 fl oz 24 3 Do not apply near aquatic areas. Danitol... narrow I — — — short high high extra high very low very low 10/2014
F
Warrior II Summer 5

3A

1.28–2.56 oz 24 14 Do not apply near aquatic areas. Warrior... broad I high high high moderate intermediate low extra high low high 10/2014
B
Intrepid 2F Summer 5

18

8–16 fl oz 4 14 — narrow II low low low short very low low low very low low 10/2014
H
Imidan 70-W Summer 5

1B

4–4.33 lb 72 14 Do not apply after hull split reaches 10... broad I high high high moderate to long intermediate low high intermediate high 10/2014
A
Entrust # Summer 5

5

1.25–3 oz 4 1 — narrow II moderate moderate 13 moderate short very low low low very low low 10/2014
A
Success Summer 5

5

4–6 oz 4 1 — narrow II moderate moderate 13 moderate short very low low low very low low 10/2014
—
No information.
I
Do not apply or allow to drift to plants that are flowering including weeds. Do not allow pesticide to contaminate water accessible to bees including puddles.
II
Do not apply or allow to drift to plants that are flowering including weeds, except when the application is made between sunset and midnight if allowed by the pesticide label and regulations. Do not allow pesticide to contaminate water accessible to bees including puddles.
III
No bee precaution, except when required by the pesticide label or regulations.
  • ‡ a b Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without personal protective equipment. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases, the REI exceeds the PHI. The longer of the two intervals is the minimum time that must elapse before harvest.
  • # a b  Acceptable for use on certified organic crops. Check with your certifier to confirm before application.
  • 1 ↩ Group numbers for insecticides and miticides are assigned by the Insecticide Resistance Action Committee (IRAC). Insecticides with unknown modes of action are assigned mode-of-action group numbers (MoAs) that begin with UN. Rotate pesticides with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a group number of 1B; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B.
  • 2 ↩ Range of insect and mite groups affected by a pesticide. Broad means the pesticide affects most groups of insects and mites; narrow means the pesticide affects only a few specific groups.
  • 3 ↩ Risk of harm to honey bees. For more information, see Bee Precaution Pesticide Ratings.
  • 4 ↩ Risk of harm to predatory mites. Toxicities are generally to western predatory mite, Galendromus occidentalis. Where differences have been measured in toxicity of the pesticide-resistant strain versus the native strain, these are listed as pesticide-resistant strain or native strain.
  • 5 a b Risk of harm to parasitoids and general predators. Toxicities are averages of reported effects and should be used only as a general guide. Actual toxicity of a specific insecticide depends on factors including the application rate, environmental conditions, and the life stage and species of a parasitoid or predator.
  • 6 ↩ Length of time residue affects natural enemies. Short means hours to days; moderate means days to 2 weeks; and long means many weeks or months.
  • 7 ↩ Risk of harm to fish from leaching, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
  • 8 ↩ Risk of harm to fish from adsorbed runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
  • 9 ↩ Risk of harm to fish from solution runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
  • 10 ↩ Risk of harm to humans from leaching, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
  • 11 ↩ Risk of harm to humans from solution runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
  • 12 ↩ Date information was last updated in the UC IPM Pest Management Guidelines.
  • 13 a b Toxic to some natural enemies (lacewing and syrphid fly larvae, predatory beetles, and thrips) when sprayed and up to 5 to 7 days after.
UC Peer Reviewed Logo

UC IPM Pest Management Guidelines: Pistachio
UC ANR Publication 3461

R.H. Beede (emeritus), UC Cooperative Extension Kings County

W.J. Bentley (emeritus), UC IPM and Kearney Agricultural Research and Extension Center, Parlier

K.M. Daane, Kearney Agricultural Research and Extension Center, Parlier

D.R. Haviland, UC IPM and UC Cooperative Extension Kern County

Acknowledgement for Contributions to Invertebrates

R.E. Rice, Kearney Agricultural Research and Extension Center, Parlier

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