1. Aphids (many species).
Tiny, pear-shaped; long antennae; two tubes projecting rearward from abdomen.
Tiny, pear-shaped; long antennae; two tubes projecting rearward from abdomen.
Host/Range: Most fruits and
vegetables, flowers, ornamentals, shade trees. Found throughout North America.
Damage: Aphids suck plant sap, causing foliage
to distort and leaves to drop; honeydew excreted on leaves supports sooty mold
growth; feeding spreads viral diseases.
Control: Wash plants with strong spray of water;
encourage native predators and parasites such as aphid midges, lacewings, and
lady beetles; when feasible, cover plants with floating row cover; apply
hot-pepper or garlic repellent sprays; for severe problems, apply horticultural
oil, insecticidal soap, or neem.
2. Cabbage maggot (Delia
radicum)
Adults: 1⁄4-inch gray flies. Larvae: white, tapering maggots.
Adults: 1⁄4-inch gray flies. Larvae: white, tapering maggots.
Host/Range: Cabbage-family crops. Found throughout North
America.
Damage: Maggots tunnel in roots, killing plants
directly or by creating entryways for disease organisms.
Control: Apply floating row covers; set out transplants through slits
in tar-paper squares; avoid first generation by delaying planting; apply
parasitic nematodes around roots; burn roots from
harvested plants; mound wood ashes or red pepper dust around stems.
3.
Caterpillars (many species)
Soft, segmented larvae with distinct, harder head capsule; six legs in front, fleshy false legs on rear segments.
Soft, segmented larvae with distinct, harder head capsule; six legs in front, fleshy false legs on rear segments.
Host/Range: Many fruits and vegetables, ornamentals, shade
trees. Range varies with species.
Damage: Caterpillars chew on leaves or along margins;
droppings soil the produce; some tunnel into fruits.
Control: Encourage native predators, parasites; hand
pick; apply floating row covers; spray with Bt (Bacillus thuringiensis) or
spinosad.
4. Cutworms (several species)
Fat, 1-inch-long, gray or black segmented larvae; active at night.
Fat, 1-inch-long, gray or black segmented larvae; active at night.
Host/Range: Most early vegetable and flower seedlings,
transplants. Found throughout North America.
Damage: Cutworms chew through stems
at ground level; they may completely devour small plants; most damaging in May
and June.
Control: Use cutworm collars on transplants; delay planting; hand
pick cutworms curled below soil surface; scatter bran baits mixed with Btk
(B.t. var. kurstaki) and molasses before planting.
5.
Colorado potato beetle (Leptinotarsa decemlineata)
Adults: yellow-orange beetles with 10 black stripes on wing covers. Larvae: orange, hump-backed grubs with black spots along sides. Eggs: yellow ovals, laid in upright clusters.
Adults: yellow-orange beetles with 10 black stripes on wing covers. Larvae: orange, hump-backed grubs with black spots along sides. Eggs: yellow ovals, laid in upright clusters.
Host/Range: Potatoes, tomatoes,
eggplant, petunias. Found throughout North America.
Damage: Beetles defoliate plants, reducing yields or
killing young plants.
Control: Apply floating row covers; use deep straw mulches; hand pick; attract native
parasites and predators; spray with Beauveria bassiana or spinosad; spray with
neem.
6. Mexican bean beetle (Epilachna varivestris)
Adults: oval, yellow-brown, 1⁄4-inch beetles with 16 black spots on wing covers. Larvae: fat, dark yellow grubs with long, branched spines.
Adults: oval, yellow-brown, 1⁄4-inch beetles with 16 black spots on wing covers. Larvae: fat, dark yellow grubs with long, branched spines.
Host/Range: Cowpeas, lima beans, snap beans, soybeans.
Found in most states east of the Mississippi River; also parts of Arizona,
Colorado, Nebraska, Texas, Utah.
Damage: Adults and larvae chew on
leaves from beneath, leaving characteristic lacy appearance; plants defoliated
and killed.
Control: Apply floating row covers; plant bush beans
early; hand pick; plant soybean trap crop; put out lures to draw spined soldier
bugs (predators) to your yard. Spray Beauveria bassiana, insecticidal soap, or
neem.
Host/Range: Most vegetable crops. Found throughout
North America.
Damage: Adults chew numerous small, round holes
in leaves; most damaging to young plants; larvae feed on plant roots.
Control: Apply floating row covers; repel the
pests by spraying plants with garlic spray or kaolin clay; for a serious
infestation, try repeated sprays of Beauveria bassiana or spinosad.
8. Tarnished plant bug (Lygus
lineolaris)
Fast-moving, mottled, green or brown bugs, forewings with black-tipped yellow triangles. Nymphs: similar to adults, but wingless.
Fast-moving, mottled, green or brown bugs, forewings with black-tipped yellow triangles. Nymphs: similar to adults, but wingless.
Host/Range: Many flowers, fruits, vegetables. Found
throughout North America.
Control: Adults and nymphs suck plant juices,
causing leaf and fruit distortion, wilting, stunting, and tip dieback.
Damage: Keep garden weed free in spring. Apply
floating row covers; encourage native predatory insects; spray young nymphs
with Beauveria bassiana or neem.
9. Japanese beetles (Popillia
japonica)
Adults: metallic blue-green, 1⁄2-inch beetles with bronze wing covers. Larvae: fat, white grubs with brown heads.
Adults: metallic blue-green, 1⁄2-inch beetles with bronze wing covers. Larvae: fat, white grubs with brown heads.
Host/Range: Many vegetables and flowers, small
fruit. Found in all states east of the Mississippi River.
Damage: Adults skeletonize leaves, chew flowers,
may completely defoliate plants; larvae feed on lawn and garden plant roots.
Control: Shake beetles from plants in early
morning; apply floating row covers; set out baited traps upwind of your garden
on two sides and at least 30 feet away; apply milky disease spores or
Herterorhabditis nematodes to soil; spray beetles with insecticidal soap.
10. Scales (more
than 200 species)
Adults: females look like hard or soft bumps on stems, leaves, fruit; males are minute flying insects. Larvae: tiny, soft, crawling larvae with threadlike mouthparts.
Adults: females look like hard or soft bumps on stems, leaves, fruit; males are minute flying insects. Larvae: tiny, soft, crawling larvae with threadlike mouthparts.
Host/Range: Many fruits, indoor plants, ornamental
shrubs, and trees. Found throughout North America.
Damage: All stages suck plant
sap, weakening plants. Plants become yellow, drop leaves, and may die. Honeydew
is excreted onto foliage and fruit.
Control: Prune out infested plant parts; encourage native predators; scrub scales
gently from twigs with soft brush and soapy water, rinse well; apply dormant or
summer oil sprays; spray with neem oil.
reprint Organic Gardening
No comments:
Post a Comment
Please leave a comment or ask a gardening question.