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Lady beetle Organic Alterntives

APHIDS

aphidsDescription: These insects can range in size from 1.5 to 4 mm in size (1/16 to 3/16 inch), and always have an appendage that looks like a 'tailpipe' extending from each side of the abdomen. Color ranges from green to yellow, pink, or from brown to black. The adult stages may have wings. They are able to reproduce asexually and can be born 'pregnant', producing up to 50 generations in a single Texas year. Aphids cause damage to plants by piercing plant tissue and sucking out fluids.

Diagnosis: Distorted growth at and above the infestation, and leaves at or below the infestation are sticky from honeydew excretions or black from the sooty mold that grows on the honeydew. Severe infestations are also covered with the shed skins of molting aphids. With a magnifying lens, look for the 'tailpipes' on the insects' abdomens.

Controls: Parasites: Aphidius matricariae (Green Peach Aphid). Aphidius colmani attacks both green peach aphid and melon aphid. Aphelinus abdominalis attacks the potato aphid. Parasitized aphid 'mummies' appear as a brown or gray papery shell with an exit hole in abdomen. Do not confuse these with the tan, white or gray molted skins. Predators: Aphidoletes aphidimyza is used for summer applications. Hippodamia convergens, or Ladybeetles, are predatory on many plant pests, as is the Green Lacewing, Chrysoperla carnea.


 

MEALY BUGS

Description: These are soft bodied insects about 1.5 to 5 mm (1/16 to 3/16 inch), usually covered with fluffy, white, mealy or waxy secretions, usually with a fringe of waxy filaments. The long-tailed mealybug has 2 to 4 posterior filaments almost as long as its body. Immature 'crawlers' are usually clear or a light yellow color. Some mealybugs are very woolly or cottony. Watch for the predatory Cryptolaemus, whose larvae look very similar to mealybugs, but much bigger (6 mm or 1/4") and faster moving. The adult Cryptolaemus look like small black ladybeetles with orange or orange-brown heads.

Diagnosis: Mealybugs feed on all parts of plants, some feeding on roots as well. They are especially troublesome on houseplants wintering over indoors. Look first in the nodes of leaves and on the underside of lower foliage for beginning infestations. Large populations produce the honeydew and thus sooty mold on lower leaves, yellow leaves, and eventual defoliation and death. Egg sacs, like the mealybugs, are covered with the same waxy filaments.

Controls:Predators: Cryptolaemus montrozieri, Leptomastix dactylopii. Clean up any new mealies or egg sacks with a cotton swab and alcohol before they spread.


 

SPIDER MITE

Description: These almost microscopic mites look like tiny jelly beans with eight legs. Body color ranges from dark red to almost clear. They stab the leaf tissue and then suck the fluids out, giving the leaf a sand-blasted look. Easily visible with a small magnifying glass, 'red' spider mites range from orange-pink to dark red. 'Two-spotted' mites are usually a light yellow with a red spot on either side of the abdomen.

Diagnosis: In severe infestations, plant leaves and terminals are covered with fine webbing and the plants appear dried, burned, or 'sand-blasted'. Affected foliage can take on a silver or bronze color. Diagnose an infestation by tapping a suspect leaf over a piece of white paper in good light. This will reveal tiny reddish dots moving around on the paper.

Controls: Predators: Phytoseiulus persimilis (65-80 degrees), Mesoseiulus longipes (70-90 degrees), Neoseiulus californicus (70-90 degrees), Galendromus occidentalis (70-95 degrees), Orius sp., Chrysopa carnea. A combination of P. persimilis (voracious feeder, short lived) with a longer lived mite like N. californicus will provide quick knockdown and extended control. Spray foliage with a strong stream of cool water to dislodge mites. Keep plants healthy and remove any weak or infected leaves and plants. Do not over fertilize as excess nitrogen can increase mite populations.


 

LEAFMINER

leafminerDescription: Leafminers are the larvae of certain insects, usually sawflies, hatched from eggs laid inside the leaf. They tunnel and feed on the mesophyll inside the leaf. They are especially fond of chrysanthemums and columbines.

Diagnosis: These larvae leave serpentine, white or yellow trails all over leaf surfaces as it tunnels and feeds inside the leaf. These tunnels are usually visible from the top and bottom of the leaf. They may coalesce to form patches on the leaves.

Control: When ready to pupate, these larvae chew a hole in the leaf and drop to the ground. They can be controlled by removing and disposing of affected foliage as the damage is noticed and before they have the chance to pupate. Chrysanthemums can be cut to the ground after bloom. Remove old leaves of species columbine after they have produced seed. Parasites: Diglyphus isea, Dacnusa siberica.


 

WHITEFLY

Description: This can be a serious pest in interiorscapes and outdoor landscapes. These small white-winged insects will flurry around like snow when a host plant is disturbed. Adults have 2 sets of white wings and look like tiny moths when they fly. Immature stages can look like scale insects on the undersides of leaves.

Diagnosis: Heavy populations can cause the black, 'sooty mold' that grows on the insects honeydew excretions. Clouds of these small white insects flurry around disturbed foliage. The most damaging whitefly are the Sweet Potato Whitefly and the Greenhouse Whitefly. A recent addition to these are the Giant Whitefly, which, can reach 4 mm (1/16 inch), and produce an odd, angel-hair like material that can hang down from the bottom of the leaves like a white beard. Carefully look under leaves for adults and immature whiteflies.

Control: Parasites: Eretmocerus californicus, Encarsia formosa, Delphastus pusillus (especially Sweet Potato Whitefly) Predators: Orius sp. In interiors, increase air movement within plantings.


 

SCALE INSECTS

Description: Scale insects occur in many different forms, from flat spots no larger than a pinhole to quarter-inch waxy turbine shaped bumps on leaves and stems of host plants. Armored scales are covered with a protective wax-like covering and cast skins from moltings. Soft scale have protective coatings that are actually hardened parts of their bodies. Some scale appear soft and fluffy similar to mealybugs. Females start out as tiny crawlers that soon attach to the plant and loose their legs. Males are only present at breeding time.

Diagnosis: Scales cause damage by sucking the sap from plants leaves and stems. Plant parts can become literally covered with scale bodies. The honeydew excretions with the accompanying sooty mold can build up on lower leaves and other surfaces under the plant. The presence of ants is also a good indicator of a scale infestation.

Control:Parasites: Metaphycus helvolus for Black, Hemispherical, Nigra & Brown Scale. Aphytis melinus for California Red, Oleander, Yellow, and Dictyospermum Scale. Predators: Clilocorus nigrica for Florida Red Scale. Lindorus lophanthe and Lacewing larvae for many scale species.


 

LACE BUG

Description: These true bugs are named for their transparent, veined wings with lacy patterns. They attack a wide variety of plants, sucking the fluids from the undersides of the leaves, giving a stippled look to the leaves.

Diagnosis: Their damage is similar to, but much coarser than that of spider mites, and is accompanied by small darks spots of excrement and shed skins. Webbing will not be present unless spider mites are also present (which is not unusual). Favorite tree hosts are sycamore and oak, where they over winter under the exfoliating bark. They also commonly attack boston ivy and pyracantha. The nymphal stages do not have the lacy wings of the adults, but are spiny and black, resembling a tiny shield beetle. Even at early stages, the dark excremental spots are visible. Use a hand lens to spot the unique wing patterns of the adults.

Control: Lacewing larvae, assassin bugs, minute pirate bugs, spiders, and predator mites.


 

THRIPS

Description: A thrips is a very small insect (1-2 mm long) that feeds on the flowers and foliage of plants by rasping the surface cells and sucking the juices that leak out. The adults have 2 wings, usually clear and fringed with hairs. They range in color from yellow to green and brown to black, sometimes banded or striped at the abdomen. The nymphs are wingless and may also be clear or yellow.

Diagnosis: Thrips damage on foliage is similar to spider mite and lace bug damage. The leaves have a stippled look and the dark excremental spots are present. There is no webbing unless there are also spider mites present as well. The affected foliage tends to bronze or bleach out. Flowers damaged by thrips are distorted or tracked with white trails. Infested flowers sometimes fail to fully open. Terminal foliage can become distorted in heavy infestations. Use a hand lens to identify these insects. Since they tend to move very quickly and hide in flowers or leaf folds, try shaking a suspect plant into a box to dislodge hidden thrips.

Control: Orius species and predatory mites such as Neoseiulus cucurmeris, N. barkeri, and Amblyseius degenerans


 

CULTURAL CONSIDERATIONS

It has been proven that many insect pests are attracted to unhealthy, stressed plants with yellow leaves. In fact, yellow cards with sticky surfaces are used to monitor insect populations. It has also been shown that healthy plants have less insect and disease problems. Many horticulturists believe that plant nutrition and health is a primary factor in pest and disease management.

When treating an insect or disease problem, it is a good idea to look at the general health and growing conditions of the plants and that of those around them. If possible, do not just treat the plant pest, but try to correct the cultural problems as well. If nothing else, a healthy plant will recover faster than a stressed plant.


 

A WORD ABOUT ANTS

Many ants nurture many of these insects for their sweet "honeydew" excretions. They will actually raise and protect their "herds" of insect pests much the way dairy farmers husband their cattle! If these ants are not controlled, no natural control program can be successful.

Ant baits with IGR's (insect growth regulators) have been successful in controlling some ant populations, especially indoors. Products such as Logic and Amdro, when used properly, can keep protein eating ant colonies under control. Sweet baits with boric acid can be used to reduce populations of sugar-feeding ants. Sugar feeders are the most troublesome to biological control programs.

When populations drop below the level necessary to care for the brood, they become cannibalistic, feeding on and reducing the amount of larvae and eggs in the colony until they can build up their population.


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