Integrated Pest Management for Raspberries

Dormant and Pre-Bloom

Acknowledgements

Nooksack IPM Advisory Committee

Introduction

Dormant and Pre-Bloom

Key Pests
Biology
Monitoring
Scouting Report
Matrix - Insects
Matrix - Diseases

Bloom/Pre-Harvest

Harvest Period

Post-Harvest

Insect Identification Sheets

Disease Identification Sheets

Tables and Charts

Pesticide Selection

IPM Resources

Pesticides and Water

Biology

Climbing Cutworms (Decision Making Guide) (Images)
Large caterpillars may be present as buds begin to swell and break. They are active at night, feeding on primary buds and new growth. Infestations are usually spotty within a field. Early season cutworms are rarely a problem, but if present, they can reduce yield measurably.

Obliquebanded Leafroller (Decision Making Guide) (Images)
The larval stage of this insect is the dominant stage found during April and May. OBLR overwinters in the larval or worm stage, often in leaves trapped between canes. As new leaves are formed in the spring, these insects crawl onto the new foliage where they feed on and roll leaves. The feeding does not usually cause significant damage to the plant but the second generation of leafroller caterpillars can be a harvest contaminant in July and August. Obliquebanded leafroller (OBLR) moth flight may start in late May, but peak moth activity and highest pheromone trap counts are usually not seen until late June and early July.

Black Vine Weevil (Desicion Making Guide) (Images)
Most black vine weevils at this time of the season are in the larval or pupal stage. They are most commonly found in the plant row within the top 6" of soil. The white larva feeds on raspberry roots until it pupates and then finally emerges as an adult weevil (snout beetle) usually beginning in mid-May.

Clay Colored Weevils (Decision Making Guide) (Images)
This weevil, which is slightly smaller than the black vine weevil, begins emerging very early in the season as buds break and new leaves are just forming. For this reason, it is also called the "bud weevil". This weevil is not widespread, but in some years and in some fields, it can cause significant damage to developing shoots and therefore it can impact yield.

Raspberry Crown Borer (Decision Making Guide) (Images)
This insect requires two years to complete its life cycle. First year larvae overwinter in cells just below the bark at the base of canes. They are white and about 1/4 inch long. They begin to feed in early March on cane buds around the plant crown. They will then bore into the canes during the spring. Their feeding causes swelling at or below the soil surface. Infested canes become spindly and canes often break off at ground level. Damaged canes often have uneven bud break or young laterals which collapse. Evidence of crown borer damage cannot be ignored as the pest population can increase rapidly.

Western Raspberry Fruitworm (Decision Making Guide) (Images)
Overwintering fruitworm beetles emerge from the soil during April and May. This small (1/6-inch long) yellowish brown beetle feeds on fruit buds and unfolding leaves during the early season. The beating tray is a useful tool for monitoring adult fruitworm activity prior to and during bloom. The best time to control this insect when it is numerous is prior to bloom and before it begins laying eggs. There is no established threshold for adult fruitworm. Counts of 1-2 beetles per 10 trays have been recorded in late April and early May with no reported damage to fruit.

Spur Blight (Decision Making Guide) (Disease Cycle) (Images)
This common cane disease appears as cracked gray areas on canes around buds. Tiny black pimples form in affected areas. This disease is initially managed by a delayed dormant lime-sulfur application, followed by 2 to 3 early summer (mid-May to early-June) fungicide applications.

Cane Blight (Decision Making Guide) (Disease Cycle) (Images)
Infected tissue appears as reddish lesion up the cane from a wound site. The best timing for fungicide applications is immediately after harvest, but inspection during the dormant and pre-bloom period confirms presence of the disease.

Yellow Rust (Decision Making Guide) (Images)
This disease first appears as a yellow pustules (aecia) on upper and lower leaf surfaces near the wire. This initial stage of infection is not usually visible until mid- to late- April. These aecia produce spores called aeciaspores, which subsequently give rise to secondary foliar infections called uridia. It is the uridia stage which repeatedly produces spores during the summer and is very difficult to control with fungicides. Late in the season, the uridia produce spores which allow the fungus to overwinter and reinfect foliage the following spring. These overwintering spores are called teliospores. Management of yellow rust focuses on:

• Delayed dormant lime sulfur to reduce viability of teliospores,
• Protectant fungicide application(s) to stop infection from aeciaspores, and
• Delaying cane tying until after leaves have dropped in the fall. 

Phytophthora Root Rot (Decision Making Guide) (Images)
When present, this microscopic fungus is able to survive in the soil for several years. When soil temperature and moisture are favorable, it produces a swimming stage called a zoospore which enables it to infect healthy plant roots. In fields which are infected with this fungus, optimum discharge of zoospores occurs when soils become completely saturated with water. Many fields are free of this disease, and therefore soil-applied fungicides should not be used as a preventative unless Phytophthora symptoms are present and the disease causing organism has been identified through laboratory analysis of root and crown tissue.

Monitoring

March

Climbing Cutworm (Decision Making Sheet) (Images)

• Examine buds and new growth in several areas within each field for signs of cutworm feeding in late March and early April.
• Where damage is found, search base of plant during day to identify the pest. If not found, check at night with a flashlight when worms are active.

Weevils (Desicion Making Sheet) (Images)

• Check soil around base of plants at several sites in a field for weevil larvae. 
• Plan on summer treatments if weevils are commonly found. 

Raspberry Crown Borer (Decision Making Sheet) (Images)

• Pay particular attention to weak areas in the field which have smaller, spindly canes or canes that break at the base when tying up to the wire in the winter and spring.

Cane Disease (Decision Making Sheet)

• Examine canes for spur blight which appears as cracked, gray areas on canes around buds. Tiny black pimples form in affected areas. The severity of this overwintering stage of spur blight can be recorded using a scale of zero (no disease) to three (wide-spread) at each of 3-5 sites in a field.
• Examine canes at catcher plate height for cane blight (less common) by scraping bark away to see vascular tissue.

Phytophthora Root Rot (Decision Making Sheet) (Images)

• Note any low areas which remain wet, particularly after winters of heavy rainfall.
• Return to these areas in June with onset of hot weather to evaluate Phytophthora symptoms.

April thru Mid-May

Clay Colored Weevil (Decision Making Sheet) (Images)

• Look for leaf flagging, bud damage, and notching of leaves; all evidence of clay colored weevil feeding. 
• If you suspect this insect is present at damaging levels, sample at night using a beating tray to confirm. (Use of the beating tray is described in detail in the Bloom and Pre-Harvest section.)

Leafrollers (Decision Making Sheet) (Images)

Monitoring OBLR larvae (Decision Making Sheet) (Images)

• Check 4-5 sites in each field to determine the percentage of leafroller infested hills. For example, in a 20-acre field subsample the field so that each of the five places you stop represents a different acre: a corner acre, a middle acre, an edge acre, etc.
• Select 20 hills/plants at each site and examine shoot tips for presence of caterpillars.
• Examine a maximum of 5 shoot tips/hill to determine if the hill is infested.
• Once an infested shoot tip is found, do not examine any more shoot tips at that hill, and record that hill as infested. If you examine five shoot tips without finding any caterpillars, record that hill as clean.
• Record the number of infested hills for each site that you sample.
• Add up the total number of infested hills that were detected and divide by the total number of hills that you examined. Multiply this number by 100 and you have the percentage of leafroller-infested hills. 
• If 10% or more hills are infested, then a spray may be advisable to control this overwintering spring generation prior to bloom.
• Sample fields for larvae at least every two weeks in April and May. This insect can also be detected using the beating tray sampling method but action levels based on this monitoring tool have not been established.

OBLR Pheromone Traps (Decision Making Sheet) (Images)

• Place Obliquebanded leafroller (OBLR) pheromone traps out in the field in mid-May. These traps use a sex attractant to monitor the male OBLR moth. There is no correlation established between the number of moths caught and the damage potential from this insect. BUT, trap catch can be used to determine the infestation from second generation caterpillars, which can be a harvest contaminant during July and early-August. 
• Place one or two traps in each field, approximately ten feet from the windward edge of the field. 
• Hang them from the top trellis wire near canopy height. 
• Check traps regularly by removing, counting, and recording the number of OBLR moths.
• Replace pheromone lure as suggested by manufacturer (usually at four week intervals). 

Climbing Cutworms (Decision Making Sheet) (Images)

• Continue monitoring for cutworm feeding activity. 
• Concentrate monitoring in areas where there is noticeably less shoot growth...it may be due to cutworms. 

Western Raspberry Fruitworm (Decision Making Sheet) (Images)

• Monitor by taking ten beating tray samples from each of four - five sites distributed across a field. 
• Record the number of adults detected at each site. 
• Examine fruit buds for signs of adult feeding and pay attention to feeding damage to leaves, which appears as slits between the veins on unfolding leaves. 
• Consider treating adult beetles prior to bloom if they are detected at most sites. 

Raspberry Crown Borer (Decision Making Sheet) (Images)

• Crown borers are in the caterpillar stage at this time of the season, feeding on and within lower canes and crown tissue. Their feeding causes swelling or galls at or below the soil surface. 
• Examine canes and crown tissue in areas of a field which show symptoms associated with damage from crown borer.

Yellow Rust (Decision Making Sheet) (Images)

• Starting in late April, examine the oldest leaves on developing laterals near the wire for infection. This procedure can be integrated into mite counting which usually begins in late April or early May. 
• Watch closely to determine when these pustules begin to sporulate. Fungicides can be applied to protect new foliage as sporulation begins.

Spider Mites (Decision Making Sheet) (Images)

• Start sampling for spider mites usually in early May. 
• Examine leaves using a 10X hand lens for presence of mites and mite predators. 
• Collect ten leaflets per site from a minimum of four sites distributed throughout a field. 
• Count the number of spider mites and mite predators and record information at each site. 
• Make note of the predominant mite stage (recent hatch, mixed, or mostly adult). 
• Estimate spider mite egg density by observing the ratio of eggs to spider mites on a leaf or two. 
• Mite samples should be taken at least every two weeks during May and June.
• The following should be recorded:
  • Spider mites
  • Predatory mites and eggs
  • Stethorus adult
  • Stethorus larvae
  • Minute pirate bug
• Stethorus is the most effective mite predator in raspberries, but is also very sensitive to the pyrethroid insecticides commonly used prior to harvest for weevil control. Stethorus is easiest to find in the early spring when the small black adults can be seen on the underside of leaves.

Scouting Report - Dormant through Pre-Bloom (PDF File)