The
Online Gardener's Handbook 2010
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| Symptom | Possible Causes |
|---|---|
| Pieces of leaf or flower missing | Caterpillars, Weevil adults (on flowers) |
| Notched leaf borders | Root weevil adults |
| Entire leaves or flowers missing | Larvae or adult beetles, Sawfly larvae, Grasshoppers, Slugs/Snails |
Damage to fruit or fruiting vegetables
| Symptom | Possible Causes |
|---|---|
| Depressions | Plant feeding bugs |
| Holes | Fruit-feeding caterpillars, Fruit-feeding beetles, Maggots |
| Irregular surface (bumpy) | Plant-feeding bugs |
| Shrivelled/misshapen | Aphids, Sawflies |
| Silvery surface | Thrips |
| Early fruit drop | Maggots, Weevils |
Discoloured Leaves
| Symptom | Possible Causes |
|---|---|
| Bleached leaves | Lace bugs |
| Bronzed leaves | Spider mites, Plant bugs |
| Silvered leaves | Thrips, Mites |
| Stippled leaves | Leafhoppers |
| Streaked leaves | Aphids, Psyllids, Thrips |
| Brown leaf edges | Leafhoppers |
Parts of Plant are Distorted
| Symptom | Possible Causes |
|---|---|
| Mined leaves | Leafmining caterpillars and maggots |
| Skeletonized leaves | Beetle larvae or adults, Some caterpillars, Sawfly larvae |
| Curled/cupped leaves | Aphids, Leafrollers |
| Galls on leaves, stems, flowers, twigs | Thrips, Gall wasps |
| Twisted growing points | Gall flies, Psylids, Eriophyid mites |
Parts of Plant Die
| Symptom | Possible Causes |
|---|---|
| Dying leaves, twigs, branches | Twig pruners, Shoot borers |
| Whole plant dying | Root-feeding beetle larvae, Vegetable maggots, Some caterpillars, Wireworms (vegetables) |
| Bark splitting/tunnelling under bark | Boring insects, scales (large infestations only) |
| Wilting | Root-feeding beetles, Root-feeding caterpillars, Aphids/Leafhoppers (large infestations only) |
| Poor seedling health/seedlings don't emerge | Wireworms, Millipedes (occasional), Maggots, Root-feeding caterpillars |
| Stems cut/plants falling over | Cutworms, Slugs/Snails |
Damage to underground plant parts (e.g. root crops)
| Symptom | Possible Causes |
|---|---|
| Holes/tunnels Scraping/channels on outer surface Scars | White grubs Wireworms Millipedes (occasional) Root-feeding maggots |
Visible Insect Matter
| Symptom | Possible Causes |
|---|---|
| Dark fecal spots | Lace bugs, Thrips, Plant bugs |
| Honeydew, Sooty mould | Aphids, Soft scale insects, Mealybugs, Psyllids, Whiteflies, Leafhoppers |
| Silken mats | Leafrollers, Leaf tiers, forest tent caterpillar |
| Spittle | Spittlebugs |
| Tents | Tent caterpillars |
| Webs | Webworms |
| Cast skins | Aphids, Cicadas, Clearwing moth larvae, Lacebugs, Leafhoppers |
| Pitch mass | Larvae of certain kinds of moths and beetles |
| Sap flow | Larvae of certain kinds of moths and beetles |
| Pitch tubes | Bark beetles |
| Cottony waxy material | Adelgids, Aphids, Certain scales, Mealybugs, Psylids |
| Slime | Slugs/Snails |
| Holes and frass (fecal material) | Boring insects |
Learn More
For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca
| Author: | OMAFRA Staff |
|---|---|
| Creation Date: | 03 May 2010 |
| Last Reviewed: | 24 June 2010 |