Integrated Pest Management Guide

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MONITORING

Monitoring for insects is like doing detective work. "Monitoring" simply means sampling on a regular basis, usually weekly. Monitoring is recommended to find pests on cranberry and to be aware of the damage they may cause. Monitoring may be done by a paid cranberry pest management consultant, or by a farm employee trained in monitoring techniques and record-keeping. Several monitoring methods are used to find different species of pests and to gather information that will help growers decide on the type and timing of treatment. Visual sweeps, sweep-netting in the daytime or at night, walking counts, pheromone traps and light traps may be used to detect the presence and the developmental stage of insect pests in cranberry fields. Monitoring for dead pests at a safe interval after a pesticide application is recommended to check that the treatment was effective and to see if newly hatched larvae are present.

In British Columbia, monitoring begins early in the spring by looking for larvae of the blackheaded fireworm. Monitoring for this pest requires a lot of observation. The method used to find these larvae is visual sweeping: crouching down to examine cranberry uprights. This technique is explained in detail in the section "KEY PESTS: DORMANT TO PRE-BLOOM; Blackheaded Fireworm; Monitoring". When damaged uprights are found it is important to record the size and number of larvae per sample before making a decision on treatment. Maps of each bed showing location of sample sites, records of larvae found, damaged areas and "hot spots" where larvae are numerous should be done at each visit. Mapping these areas allows growers to go back to precise spots and check for dead larvae after a treatment, and gives information on the area to watch for infestations year after year. Visual sweeps provide a good opportunity to collect unknown pests feeding on cranberry foliage for further identification.

In the Pacific Northwest, sweep-netting is used mostly at night to find cutworm larvae and adult weevils feeding on the cranberry foliage. A long-handled sweep net 37.5 cm (15 inches) in diameter is drawn across the tips of the vines as the person sweeping walks through the bed. One "sweep" is a 180-degree arc around the person sweeping. One "sweep set" refers to a number of sweeps (10, 20 or 25) taken as the person walks through the bed. It is recommended to take as many sweep sets as practical, some from the edges and some from the middle of the beds. Sometimes other pests can be found in the net at the same time. Sweep-netting during the daytime for fireworm larvae is not usually done in Western Canada.

Walking counts can be used to estimate the number of girdler moths flying over areas of the beds. Where many girdler moths are seen, many eggs will probably be laid by female moths. Walking counts help predict where damage may be done by larvae in the following months. Walking counts are explained in detail in the section "KEY PESTS: BLOOM AND FRUIT-SIZING TO HARVEST; Cranberry Girdler; Monitoring".

Pheromone traps are baited with a synthetic pheromone (sex attractant) to draw male insects (usually moths) into a trap where they are confined or trapped on a sticky surface. Pheromones are usually species-specific, although non-target pests are sometimes caught in pheromone traps baited with the pheromone of a target pest. Pheromone traps provide information on the presence or absence of the target species, the time at which the first moths fly and the peak of moth flight, which is useful in predicting the timing of the next generation of larvae. Target moths in pheromone traps should be counted at least once a week (on the same day each week) and dead moths should be removed from the bottom of the traps.

Light trapping can be used to trap moths for which synthetic pheromone lures are not commercially available. The usual light trap consists of a blacklight tube and two to four baffles hung vertically over a bucket. At night, flying moths are attracted to the light and fall into the bucket through a funnel located at the base of the black light tube. Traps should be checked every morning to collect good specimens for identification. These traps will attract flying insects from adjacent fields or forests, bringing great quantities of many species of insects. Information collected during all types of monitoring should be recorded and kept at the farm for reference.


Sweep-netting	Pheromone trap


Light trap for night-flying moths

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