Vegetable Pests

(of the Southeastern USA)

Order Lepidoptera:Squash Vine Borers

1952 USDA Yearbook Plate on Squash Vine Borer life cycle and damage.

Squash Vine Borers attack the stalk and vine of squash plants.

Bt or insecticial soap sprayed at the base of plants can control squash vine borer.

Butternut squash (Machata family) are resistant to squash vine borer.

Squash Vine Borers - Melittia curcurbitae/satyriniformis - Adults are blue/black stout bodied moths with clear wings; males have a red velvet coating; larvae tunnel at the base of the stalks. Controls - Gently split stalks and remove larva by hand - bury or tie split stalk to heal. Remove infested material. Trap/watch for adults - Bt, or soap. Tricks - Machata family squash (butternut) are more resistant to borers. Or spray Bt twice weekly at base of plant during moth flight (Late June - August).

 

 

Order Coleoptera:Family Chrysomelidae:Flea Beetles

(Phyllotreta spp. and others)

Shot holes typical of flea beetle damage.

Flea beetles lay eggs at the base of the host plant.

2 lined crucifer flea beetle.

 

Leaf on Right: flea beetle holes make it unmarketable; Leaf on left Hb nemas - leaf is marketable; 3 weeks later in same plot.


Flea beetles – different species attack different plants (like eggplant vs. brassicas).
Larvae live on the roots of the plants the adults are on. Controls – Nematode Heterhabiditis bacteriophora (Hb) attacks the larva – water them in under the plants being attacked – direct at the roots. Also, big-eyed bugs are supposed to eat flea beetle adults. Tricks – For nematodes, soil temperature must be above 55 degrees F. Critical to get healthy viable nematodes from a fresh, good source. Examine closely upon receipt. Can refrigerate good nemas for 2-4 weeks. You can apply nemas with a watering can or irrigate them in. BEST TIME IS AFTER A GOOD RAIN, BECAUSE Nemas MOVE ON A FILM OF WATER.

Broccoli Pests: Order Lepidoptera

Imported Cabbage Worm (ICW; Pieris rapae L.)

Imported Cabbageworm, Pieris rape adult feeding on mustar; note syrphid feeding nearby.

 

ICW eggs are football shaped and yellow.

A half eaten small ICW larva.

5th instar ICW caterpillar killed by Bt.

Diamondback Moth (DBM; Plutella xylostella L.)

Diadegma insulare cocoon - this wasp is an important parasitoid of DBM larvae.

DBM pupa is initially green, and then turns brown.

DBM adult has 3 diamond-shaped spots on its back.

DBM larva can be distinguished by the v-shaped legs at the back of the caterpillar.

Cross-Striped Cabbageworm (XSCW- Evergestis rimosalis Guenee'

Egg mass of cross striped cabbageworm.

Gregarious larvae of XSCW.

Feeding damage (windows) on broccoli typical for XSCW.

Cabbage Caterpillars – Imported cabbageworm, diamondback moth, cross-striped cabbageworm, cabbage looper, cabbage webworm and a few more. Predators: ladybugs, syrphids, carabids, lacewings, soldier beetles, lightning bugs and predatory midges; and Parasitoids of worms – specific trichogramma and braconid wasps – cocoons are yellow or white. See Organic broccoli tab for more information on natural enemies.

Whiteflies: Order Homoptera;

Family Aleyrodidae

Whitefly adult next to Encarsia wasp; also note T-shaped exit hole of whitefly pupa.

Whitefly nymphs on leaf.

Round exit hole of Encarsia; versus T-shaped exit hole of unparasitized

Whiteflies - what species? Most common is Greenhouse whitefly (Trialeurodes vaporarum) wings held roof like over body); others include Silverleaf whitefly (Bemisia argentifolii) and Ash Whitefly (Pome Fruits). First Instar larvae are crawlers, and then become sessile nymphs. Sooty mold from honeydew. Controls: Parasites: Encarsia formosa for Greenhouse Whitefly; other Encarsia wasp species specific to each Whitefly (almost). Tricks – Encarsia can out reproduce the whiteflies by 2X if the temperature in the greenhouse is above 75 degrees Fahrenheit. Look for parasite’s “bullet like” exit hole (like in the movie Alien) vs. regular exit holes (T-shaped) on the pupa – determine % parasitization. Predators: Whitefly predator Delphastis pusillus, others include ladybugs, lacewings, and predatory bugs. There are also some whitefly fungal diseases available – Verticillium lecani.

Aphids - Order Homoptera

Family Aphidae

Aphids on okra - ant is tending them.

Aphid mummy on broccoli - see exit hole.

Green Peach Aphid on broccoli.

C7 ladybug feeding on fennel aphids.

 

Aphids - dozens of species; some are specific to certain families of plants, and others are across species plant feeders. Anticipate aphids and release beneficials ahead of time to control aphids before they get a head start. Aphids (almost all are clones) are born pregnant! Aphids can reproduce at temperatures lower than most beneficials, so this is why aphids become a problem in the winter in greenhouses. Up the temperature for a good part of the day and your beneficials will out reproduce the pest. Controls - ladybugs, lacewings (work on Oleander aphids, which are poisonous), syrphid larva, Predatory midge (Ceciomyiidae) larvae (orange maggots), there are also several specific parasitic wasps- (Aphiidae & Aphelinidae).

Plant feeding Bugs; Order Hemiptera

Family Pentatomidae and others

Harlequin Bug feeding damage on broccoli.

Broccoli plants infested with Harlequin Bugs are stunted.

Mating Harlequin bugs on mustard - we use mustard as a trap crop.

Squash bug nymph feeding.

1952 USDA Yearbook plate on Squash bug - note fly parasitoid of adult bug.

 

Stink bugs/Harlequin bugs/ Squash Bugs - don't have continuous crucifers/ cleome. Controls: egg parasites, Trissolcus bassalis, T. murgantia, Ooencyrtus johnsoni, and several other parasitoids of adult bugs like the tachinid Trichopoda pennipes (see above under squash bug). Trap crops of mustards, radishes and cleome - remove/spray adults gathering on these plants

 

Colorado Potato Beetle; Order Coleoptera

Family Chrysomelidae

CPB eggs on young potato plant.

Partially eaten egg mass of CPB.

Adult CPB on potato.

Harmonia and other ladybugs will eat CPB eggs and small larva.

 

Colorado Potato Beetle (CPB) - Leptinotarsa decimlineata (10 lined beetle). The CPB is native to the western US, where it fed upon a solanaceous weed called buffalo burr. When the settlers introduced potatoes into its range, well, suffice it to say that CPB now gives Europeans and Russians a fit, too. Controls: a thick layer of mulch impedes beetle movement and pupation; no-till is a champion at this. Mulch also invites lots of ground beetles; Lebia spp. is specific to CPB. Farmscape to bring in egg predators like ladybeetles, bombadier beetles, lightning bugs, soldier beetles. These will all eat the eggs and small larvae of the CPB. Release healthy ladybugs from a reputable source if you need help. See ladybug release instructions under beneficials.

 

Spider Mites - nip these in the "bug". Spider mites are Arachnids - webbing and small reddish mites (2-spots; mites are the size of this dot(.) - leaves curl under. Check for mites with a loop. Controls: predatory mites (expensive but good) - get a mix of 2 or 3 species of predatory mites - different species work at different temperatures/humidities - so a mix is best. Also ladybugs, lacewings, syrphid larvae and predatory midge larvae will attack and control populations if done early enough. Rescue treatments using hot pepper wax, insecticidal soap or similar approved organic control.

Cucumber beetles - (Order Coleoptera; Family Chrysomelidae) several types Diabrotica - 3 spp. - Western (adults dark green & have W on back), Southern (12-spotted Cuke beetle), and Northern (adults are Solid Green) larvae (rootworms) are similar in life history to flea beetle larvae. Supposedly, there is bait for these - watermelon juice. Control: Trap adults; use Hb nematodes as under Flea beetles above.

Japanese beetle Popillia japonica Newman (JB)/Exotic scarabs (oriental beetle, Exomala orientalis (OB) Asiatic Garden Beetle, etc.) Order Coleoptera; Family Scarabaeidae).
JB & exotic scarab larva (grubs) live in the soil and feed on plant roots. Controls - Nematode Heterorhabiditis bacteriophora (Hb). Parasites: 1) Tiphia vernalis - wasp attacks JB/OB grubs in the soil (www.drmcbug.com); 2) Istocheta aldrichi - tachnid that attacks adult Jbs. Tricks - nemas, soil temperature must be above 60 degrees F. Critical to get healthy viable nematodes from a fresh, good source. Can refrigerate good nemas for 2-4 weeks. For Tiphia, Tulip poplar trees or a similar nearby nectar source is necessary to get high rates of parasitization.

MBB eggs and small larva on beans. MBB larva feeding on bean leaf. Normal pupa of MBB (yellow) vs. parasitized pupa of MBB (brown). Mexican bean beetle adults are coppery colored and spotted; don't confuse with Ladybugs.


Mexican Bean Beetle and Squash Beetle - Control -Pediobius foevulatus - wasp; doesn't overwinter. Timing and release amount (1000 wasps total) is critical! Release when you see EGGS of Beetles. Make two releases of wasps about 2-3 weeks apart- so you are releasing wasps that will be present when all the larvae of the bean beetle are created. Beetle larvae become mummified, turn brown, and have exit holes where the wasps emerge. These things work well in warm summers. May not work well in cool, wet summers…these wasps are tropical, so put them out after all danger of frost is past. Umbels are good food plants.