Springtails

Springtails are small,jumpy arthropods that are similar to insects.When dis-turbed,they use a forked structure on the bottom of the abdomen to jump 3 4-2 inches.They are common and abundant in the litter layer of natural ecosystems. In greenhouses, a few species cause problems occasionally on seedlings and young plants.They are unlikely to be a problem for plants grown in a soilless medium. Springtails feed on decaying matter, algae,and fungi and are normally only a nuisance. Some species,...

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Euseius hibisci feeding on citrus thrips. Neoseiulus barkeri. This phytoseiid mite formerly called Amblyseius mckenziei is still listed by some commercial suppliers, even though this species is now considered to be a strain of N. cucumeris. This predatory phytoseiid mite, previously known as Typhlodromus thripsi, feeds on young thrips.The pear-shaped adults are a pale brown and are noticeably smaller and flatter than the spider mite predator Phytoseiulus persimilis. Females lay an average of...

Soft scales

The soft scales are the more important of the two groups of scales found in greenhouses. A wide variety of the flowering and foliage ornamentals, from orchids to ferns, are good hosts for soft scales.The brown soft scale attacks a broad range of hosts, while the black scale prefers woody plants.The hemispherical scale favors ferns, asparagus fern, schefflera, and many nonwoody evergreen plants. Plants in the family Acanthaceae, such as Crossandra and the zebra plant (Aphelandra squarrosa), are...

Alternative control methods

Avoid introducing any new plant material that may contain leafminer eggs or larvae into the greenhouses. Rogue out severely infested plants. Promptly remove or destroy all crop residue containing larval leafminers that could continue to develop after harvest. Use physical barriers, such as hanging sheets of plastic, to prevent adults from flying to other areas of the greenhouse during harvest. Leafminers prefer and develop better on certain crop cultivars.A plant's chemical content, nutritional...

Slugs

Slugs are not insects but mollusks, a group that includes snails, clams, scallops, oysters, squid, and octopus. Slugs are omnivorous but prefer to eat vegetation, and they thrive in moist places like the humid greenhouse environment. Several species of both native and imported slugs may cause damage in greenhouses on most vegetable and ornamental crops, especially orchids. Slugs are nocturnal feeders that eat seedlings or chew holes in succulent leaves, stems, or roots. During the day they hide...

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The mealybug destroyer, Cryptolaemus montrouzieri, is probably the most successful natural enemy of mealybugs. shorter days of winter seem to reduce their activity, although the mealybugs will continue to increase under these conditions. Beetles are available from several commercial insectaries. Other lady beetles. Many coccinellid beetles are important predators of mealybugs in other cropping systems, but few have been investigated for biological control of mealybugs in greenhouses. Diomus...

Whiteflies

Available natural enemies and their potential for control There are a few available parasites of whiteflies. Some predators and pathogens can be used along with the parasites to improve control.The potential for successful biological control varies from moderate to high. Order Homoptera Aphids, leafhop-pers, planthoppers, mealybugs, scales, and whiteflies Greenhouse whitefly, Trialeurodes vaporariorum hiteflies infest a wide range of greenhouse crops.The greenhouse whitefly is a tropical...

Thrips

Available natural enemies and their potential for control There are some predators, pathogens, and parasites available for control of thrips. However, even when used in combination, they will provide only moderate control. Other remedies may be necessary when pest populations are high. Thrips are important pests of cucumbers, peppers, and a broad range of ornamental greenhouse crops. These very small insects commonly hide in flowers, buds, and leaf axils, and often go unnoticed until damage...

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Container of Neoseiulus californicus,a predatory mite. Phytoseiulus macropilis. This mite has been investigated for greenhouse use on dieffenbachia,dracena, parlor palm (Chamaedorea elegans), and schefflera (Brassaia actinophylla).The globose, light- to deep-red females lay oval orange eggs that hatch into six-legged larvae. Both larvae and nymphs have a similar white to light orange color. Males are identical to females in shape and color but are smaller.These mites have a strong preference...

Tarsonemid mites

These very small mites infest a wide range of host plants, and because they are so small their damage can become extensive before the population is recognized. Preferred hosts of the cyclamen mite include African violet, azalea, cyclamen, fuchsia, geranium, ivy, and snapdragon. Broad mite is an important pest of gerbera, and may also be found on other hosts including cyclamen, geranium, hibiscus, impatiens, ivy, and peperomia, as well as vegetable bedding plants such as bean, pepper, and...

Info

The soil-dwelling laelapid mite Hypoaspis miles. Nematodes. Several entomopatho-genic (insect-pathogenic) nematodes occur naturally in the soil and parasitize a variety of soil-inhabiting insects, including fungus gnat larvae. Nematodes are small,long,slender roundworms.They are about 1 64 inch (0.5 mm) long, transparent, and practically invisible to the naked eye.They require moist soil to survive.When they find an insect, they enter it through natural openings and release a bacterium that...

Armored scales

Armored scales get their name from the hard, waxy coating that covers their bodies.They are not as economically damaging in greenhouses as are other scale insects because armored scales infest limited types of plants, mainly trees and shrubs, and they don't produce honeydew.They can be important pests in conservatories. The plant damage caused by armored scale feeding is similar to that caused by soft scales.They inject toxins while feeding on leaf tissue.The toxins kill cells around the...

Symphylans

Symphylans are very active arthropods found in damp soils rich in organic matter.They are closely related to centipedes and millipedes, so are not insects.They are often confused with springtails, but symphylans are larger, have more legs, move faster, and do not jump.They tend to be found in moist soils. Symphylans are general feeders and may attack many vegetable and ornamental crops. Garden symphylans injure germinating seeds and seedlings in particular, and they can be a serious problem on...

Contemporary biological control

Biological control of insects and mites in greenhouse crops began in England during the late 1920s when Encarsia formosa was used to control greenhouse whitefly on tomatoes.The use of Encarsia stopped, however, after the development of synthetic organic pesticides in the 1940s. Using natural enemies for pest control in greenhouses became popular again in the 1960s when twospotted spider mite populations in European greenhouses became resistant to many pesticides and devastated cucumber crops....

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The fungus Paecilomyces fumosoroseus consumes its host from the inside out.The powdery spores turn the infected insect white at first, then change to shades of pink. Verticillium lecanii. This insect-parasitic fungus infects both aphids and white-flies.The fungal strain with large spores infects aphids the one with smaller spores infects whiteflies. V.lecanii grows and multiplies in the greenhouse at temperatures of 59 -77 F. Fungal spore germination and infection occurs only when the relative...