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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...

Alternative control methods

This is the most important cultural practice for preventing whitefly problems. Remove weeds, hanging baskets, or pet plantsthat serve as alternate hosts for whiteflies from both inside and outside the greenhouse. Whiteflies can easily move from an infested crop to an uninfested one. Be cautious about introducing new plant material into greenhouses. Remove and immediately destroy crop residues after harvest.Wait several days before bringing in new crops after an infested crop has been completely...

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...