MINT STEM BORER MANAGEMENT |
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Mint stem borer occurs in Idaho and Malheur County in
eastern Oregon but damage is minimal and may not be sufficient to justify treatment (Baird et al. 1990). Adults can be sampled during the daytime with
a sweep net from mid-May to mid-June. In Idaho, unpainted wooden lath stakes coated with
stickum have been used to monitor adult activity. Stakes should be placed in the field in
mid-May and checked twice weekly through mid-June. To sample for larvae, take mint stem
samples from several different locations in the field during late June through July. Cut
the stems just below the soil, split the stems, and look for larvae or feeding damage.
Stems of infested plants appear weakened near the soil surface where the eggs are laid and
the larvae are feeding. Plants appear weak with the early visible symptoms of yellowing,
wilting, and lodging. Damage from the mint stem borer is greatest in stressed plants.
Healthy, vigorously growing mint usually does not show symptoms or yield loss despite high
numbers of adults in the field. In Idaho, mint fields 3 to 5 years old or mint that is
under stress (water, fertilizer, root diseases) are most affected by this pest. |