Asparagus insect pests: asparagus beetle and asparagus miner

Understanding these two pests for better management: one feeds on fern while the other tunnels into stems.

May 23, 2011 - Author: Zsofia Szendrei, Michigan State University Extension, Department of Entomology

Two insect pests of asparagus are already present in Michigan fields: asparagus beetles and asparagus miners. In the spring, both of these insects are attracted to young fields and volunteer plants where ferns develop early, but they both cause damage to asparagus plants throughout the entire growing season.

The main difference between the two insects in terms of the severity of damage they cause is that while asparagus beetles feed on fern and thus reduce photosynthetic surface, the asparagus miner tunnels in stems and facilitates the transmission of a disease (Fusarium crown and root rot). While asparagus beetles are controlled with foliar insecticides in commercial production, the asparagus miners are more difficult to reach with insecticides because the larvae develop protected by stem tissue.

The MSU Vegetable Entomology Program is currently exploring options for management of asparagus miner larvae. Targeting adult miners with insecticides during the season requires the development of a degree-day model to be able to precisely predict when peak emergence and flight occurs based on the temperature. At this point, we are working on developing such a degree-day model for the miner.

Another area that is lacking is the availability of effective monitoring tools for these two insect species. Along with appropriate action thresholds, monitoring could help target control measures more effectively. Monitoring is sometimes done with lures that contain plant or insect derived volatile compounds that attract specific insect species. The lures are usually attached to traps that are then placed out into the field and checked on a regular basis for insect numbers. The MSU Vegetable Entomology Program is exploring options for an asparagus miner lure.

For photos and more information on the biology of these insects, please visit the following websites:

Table 1. Comparison of two important asparagus pests.
Asparagus beetle Asparagus miner
Number of generations per season 2-3 2-3
Type of damage Feeding on fern Tunneling in stems
Damaging life stage Adult, larvae Larvae
Ability to transmit disease No Yes (Fusarium)
Tools to monitor N/A N/A
Tools to control Foliar insecticides N/A
Degree day model N/A N/A

Dr. Szendre's work is funded in part by MSU's AgBioResearch

Tags: asparagus, msu extension, vegetables

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