Common insects - Id and control

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Contributed by: Mr. HIGHway
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The FAQ summarizes common indoor insect identification, symptoms and controls. Refer to pest-specific Faq?s for more information.


Signs of an infestation:
Stunted, curled leaves. Aphids use piercing mouthparts to suck sap from the Phloem. Ants often accompany aphids (Ants help transport aphids around), and will also need to be controlled. Aphids secrete a sugar-like ?honeydew?, which make the undersides of the leaves sticky.

How to get rid of aphids:
Use sticky traps (i.e. No Pest Strip) for prevention and detection. Beneficial insects like ladybugs can be used to naturally control an infestation. A soapy spray (i.e. Safer?s Soap or detergent in warm water) can also be used to suffocate them.

? Suck plant sap
? Cause stunting, leaf curling
? Leave honeydew deposits on leaves
? Ants in the grow room

Contributed by: Sniperman
Submitted: July 24th, 2004

Aphids: symptoms include curled or yellow leaves. Sticky honeydew residue on leaves, general weakness in plants.

Control: spray with a strong stream of water (during veg only). Sticky yellow traps. Alum foil mulch. Predatory bugs. Horticulture sprays. Most general-purpose garden spray r dusts, including pyrethrins, rotenone, and Malathion.

Spider Mites:

Signs of an Infestation:
Mites will first be noticed by the presence of small, discolored spots located near veins in the leaves. To see them, you will need the help of a 10X loupe, or a 30X Microscope. Mites use piercing mouthparts to suck sap. Mites will slow growth and attack the buds in advanced stages. The life cycle of the spider mite is closely tied to the temperature of the grow room; slow an infestation by keeping temp in the low 70?s.

Eliminating spider mites:
A ?No Pest strip? is very effective in eliminating them. Avid is a very effective systemic chemical control. A soapy spray will also keep their numbers in check (thoroughly coat underside of the leaves). Space plants out to minimize transfer movement between plants.

? Suck plant sap
? 'Speckling' may indicate mites underneath
? Mites may appear transparent, black or red
? 'Bronzing' of the leaf is characteristic
? Webbing is present in advanced stages

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!
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.

? Feed on plant tissue
? Rasp leaf surfaces and suck juices
? Heavily damaged plants appear silvery or gray
? Plants may be distorted, especially seedlings


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.

? 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:
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.

?Gnats vector root rot
?Gnats on the medium, or bottoms of the plants
?? long whitish maggots in the soil

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  Last modified: 13:57 - Nov 07, 2002  

faq:1333 "Common insects - Id and control"