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| Image by Sog: Thrip size reference |
Signs of an infestation:
Thrips feed on new leaves of plants (and flowers); fresh leaf growth will deformed. A metallic sheen on leaves is one sure indicator of Thrips.
Sog "Thrip feces are easy to see with the naked eye; they show up as black spots on the leaves and stems of infected areas. Thrips themselves are a pale pinkish color."
Controlling Thrips:
Interestingly, Garlic repels Thrips. Cooler temps will slow down the life cycle, and blue sticky traps will trap adults. You can siphon them off by rustling the plant, and sucking them up with a shop-vac!
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Image by Sog: Silvered leaves
indicate heavy attack |
Predator mites are also beneficial in the control of Thrips. Fine powdered Sulphur applied to the leaves will control them as well. A biological spray containing Beauvaria bassiana, (A fungus that grows and consumes Thrips) is also effective. Spraying the leaves with Chrysanthemum also kills Thrips.
Summary:
? Feed on plant tissue
? Rasp leaf surfaces and suck juices
? Heavily damaged plants appear silvery or gray
? Plants may be distorted, especially seedlings
Whiteflies:
Signs of an infestation:
Whiteflies are also sap-suckers. The top surface of leaves on infested plants become pale or spotted due to these insects feeding on the undersides of the leaves. Heavily infested plants will produce a buzzing cloud of flies if shaken.
The Whitefly life cycle is interesting in that the larval stage does all the damage. The larva will hatch and remain until it has quickly molted 3 times. Then it pupates and an adult emerges.
Controlling the Whitefly:
Insecticidal soap will take care of an infestation, as will the more toxic Diazanaon. Apply the soap (plus a wetting agent) to all parts on the plants, and both sides of the leaves. This will act to block the breathing pores and suffocate the pests.
Summary:
? feed by sucking plant juices
? mottled leaves indicate heavy attack
? may cause yellowing or death
? excreted honeydew may cover lower leaves, and black mold may grow on honeydew
Fungus Gnats:
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| Image by Ot1: Fungus Gnat |
Signs of an infestation:
Fungus Gnats are attracted to soils that are rich in compost and nutrients. They lay eggs on the surface, hatching into larvae. Those larvae feed on the root tissue, including root hairs, and the outer cell covering of the root; often leaving only the central tube of the root. External signs include discolored leaves, and systemic plant failure. Fungus gnat adults will often run across the medium and may fly if the plant is shaken.
Controlling Fungus Gnats:
Pyrethrum aerosols, as well as placing yellow sticky traps all around the plant will help control the emerging adults. Gnatrol (containing natural Bt) is highly recommended.
Summary:
?Gnats vector root rot
?Gnats on the medium, or bottoms of the plants
?¼? long whitish maggots in the soil
Links to images:
www.naturescontrol.com/pests.html