Gypsy moth identification
Caterpillars
Gypsy moth larvae, or caterpillars, are often confused with the eastern tent and forest tent caterpillars, both of which emerge in the spring and are about the same size.
To tell them apart, look at the older caterpillars.
| Gypsy moths | Eastern tent caterpillars | Forest tent caterpillars | |
|---|---|---|---|
| Markings | Five pairs of blue dots and six pairs of red dots down its back | White stripe down its back and blue markings down each side | Row of white foot print shaped marks down its back |
| Tent making | No noticeable webs or tents | Large silken tents found in branch crotches | Some silk along branches, but no tents |
| Habits | Move to bark cracks or other hiding places during the day | Hide in their tent during the day, leaving to feed at night | Cluster on bark during the day |
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Adult moths
Adult male gypsy moths are brown to gray with dark markings in a scalloped pattern along the wing edge. They have large featherlike antennae used to pick up the female pheromone, or sex attractant. Female moths are white with small brown markings and are much larger than the males.
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When might I see them?
You are not likely to see any gypsy moths in Minnesota for a long time because there are so few of them present. But once an area is infested, the fuzzy, mustard-colored egg masses can be found anytime between August and April. The female moth cannot fly, but crawls along tree trunks and objects near host trees where egg masses are deposited in crevices, under loose bark, or in protected places on objects in infested areas. Female moths will lay eggs on car wheel wells, bumpers, yard furniture, etc. Depending on how far north they are, the eggs can hatch anywhere between late April and early June. After hatching, the young caterpillars climb to the top of a nearby tree to spin a silken thread and catch the wind to the nearest preferred host tree. There they feed until time to pupate in late June through July. The adult moths begin to emerge in July in the south and August in the north. The adults do not feed; they mate and die in one to two weeks.
Southern Minnesota
- Egg masses: August
- Caterpillars: May–June
- Pupae: June
- Moths: July–August
Northern Minnesota
- Egg masses: August–September
- Caterpillars: June–July
- Pupae: July
- Moths: August