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Pest group

Caterpillars

Holes, stripped leaves and dark frass pellets; the culprit is usually on the underside or inside the fruit.

Which one do I have?
  1. BagwormsThyridopteryx ephemeraeformisCaterpillars that live in spindle-shaped bags made of silk and needles, hanging from arborvitae, juniper and other evergreens. They feed all summer, and heavy infestations can kill evergreens. The bags are easy to miss until autumn. Picking them off in winter, and spraying Btk in early summer while the caterpillars are small, are the two things that work.Evergreens & shrubs · Shade & fruit trees
  2. Cabbage wormsPieris rapae"Cabbage worms" usually means the imported cabbageworm: the velvety green caterpillar of the small white butterfly seen flitting over cabbage and kale by day. It chews big holes in the leaves, bores into heads and fouls them with green frass. Row covers keep the butterflies off, and Bt kills small caterpillars without harming the wasps that parasitise them.Brassicas
  3. CutwormsNoctuidae (Agrotis ipsilon, Peridroma saucia and others)Fat, dull grey to brown caterpillars that hide in the soil by day and come up at night to chew through the stems of young plants at or just below the soil line. One larva can fell several seedlings in a night. A collar round each transplant is the standard garden fix.Tomato · Pepper · Brassicas · Corn · Beans · …
  4. Cabbage looperTrichoplusia niA pale green caterpillar that loops like an inchworm as it walks. It chews ragged holes between the veins of cabbage, lettuce and many other crops. It migrates north each summer. Wild parasites, and Bt sprayed on young larvae, usually keep it in check.Brassicas · Lettuce & leafy greens · Spinach · Tomato · Cucumber · …
  5. Corn earwormHelicoverpa zeaThe same caterpillar is called the corn earworm in sweet corn and the tomato fruitworm in tomatoes. In corn it hatches on the silks, crawls down the silk channel and eats the kernels at the tip. In tomatoes it bores into green fruit at the stem end. Once it is inside, sprays cannot reach it, so timing is everything.Corn · Tomato · Pepper · Beans · Lettuce & leafy greens
  6. Codling mothCydia pomonellaThe moth behind the "worm in the apple". Its larvae bore into apples and pears and tunnel to the core, and UC IPM reports 20–90% of the fruit infested on untreated trees. Bagging the fruit is the one non-chemical method that works on its own; pheromone traps tell you when to act.Apple & pear · Shade & fruit trees
  7. Eastern tent caterpillarMalacosoma americanumA native caterpillar that builds a dense white silk tent in the fork of a cherry or apple branch in early spring. The caterpillars leave the tent to feed and strip the leaves around it. The tents are ugly, but trees usually leaf out again. Removing the egg masses in winter and the young tents in spring is usually enough.Shade & fruit trees · Stone fruit · Apple & pear
  8. Diamondback mothPlutella xylostellaA tiny green caterpillar, under half an inch long, that wriggles violently and drops on a silk thread when touched. It rasps brassica leaves from below, leaving see-through windowpanes, and can stunt young plants by feeding on the growing point. It resists many insecticides, some Bt products among them, so conserving its wild parasitoids is central to control.Brassicas
  9. Beet armywormSpodoptera exiguaA small green armyworm that migrates north in late summer and feeds on peppers, tomatoes, beets, lettuce and many other vegetables. Young larvae feed in groups and skeletonise leaves under fine webbing; older ones chew holes in leaves and fruit. Kentucky Extension says most Bt products do not control it and the aizawai strain does.Pepper · Tomato · Lettuce & leafy greens · Brassicas · Beans · …
  10. Cross-striped cabbagewormEvergestis rimosalisA bluish-grey caterpillar with black bands across its back that feeds in groups, because the moth lays its eggs in clusters. One plant can be skeletonised while the plants beside it are untouched. It is a late-summer pest, once mainly southern, and is now serious in southeastern New England. It is destructive enough that UMass advises treating at just 5% of plants infested.Brassicas
  11. Citrus leafminerPhyllocnistis citrellaA tiny moth whose caterpillars tunnel silvery trails through young citrus leaves and curl them up. It looks alarming, but UC IPM says trees older than about four years generally tolerate it with little or no effect on growth or fruit. On mature trees the honest advice is to leave it alone, and let its wasp parasites work.Citrus

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macro · caterpillars, side by side

At a glance

Species
11 profiled
Controls
0 beneficials
Settings
Garden, Field, Under glass
Crops
20 host crops

Caterpillars by crop

Each page is one species on one host: the host-specific control, rate and threshold.