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2014 Greenhouse insecticide labels
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Twospotted spider mite
References:
Twospotted spider mite
damage
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Time: All times of the year, but particularly during winter and early spring when greenhouses are drier Hosts: over 300 woody and herbaceous species Twospotted spider mites can occur at any time of the year in the greenhouse; however, populations are more severe in dry conditions, particularly in winter and early spring. They attack over 300 host plants; both woody and herbaceous plants are at risk. Adults are 0.4 mm long and have eight legs. They are easily recognized by the two to four black spots on the semi-transparent body. Eggs are round and transparent. Larvae have six legs, and nymphs have eight. Twospotted spider mites damage plants by inserting their chelicerae into plant tissue and sucking the contents of leaf cells. This causes characteristic stippling on the leaves. In heavy infestations, the mites produce extensive webbing over plants and can cause leaf drop. Monitor for mites by looking for damage and examining the undersides of leaves for mites and eggs. Beat plants with a stick and collect mites and eggs over a white cloth. Mites mature in 5 to 20 days depending on temperature and females lay over 100 eggs during their lives. Management: Small populations of twospotted spider mites can be managed with oils, soaps, or biological control agents. Washing leaves with water may dislodge some of the mites, and increasing the humidity in the greenhouse will make a less favorable habitat. In heavy infestations, miticides should be used. Rotate between classes of miticides to prevent spider mites from becoming resistant to the miticides.
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Darkwinged fungas
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Time: All times of the year, but particularly during winter and early spring when greenhouses are drier Hosts: Alfalfa, carnations, clover, corn, cucumbers, Easter lilies, geraniums, lettuce, nasturtium, peppers, rape, poinsettias, potatoes, soybeans, wheat, and others Darkwinged fungus gnats are small flies that commonly occur in the greenhouse. Larvae feed on roots of plants and mature in two weeks. They are white with black head capsules and reach 5.5 mm in length. Adults are small (2.5 mm long), dark gray to black, with long legs and long, filiform antennae. They live for one week and females can lay up to 150 eggs on the soil surface during that time. Adults are weak fliers and do not feed. Fungus gnats are usually considered nuisance pests, but larvae sometimes vector root rot pathogens to plants. Monitor for larvae by placing potato slices on the surface of the soil, and monitor for adults with yellow sticky cards. Wilted plants may indicate the presence of fungus gnat larvae and root rot. Management: Avoid overwatering and, when practical, use potting mixes that contain bark as opposed to peat moss. Be sure potted plants have proper drainage.
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Western flower
thrips References: Western Flower Thrips in Commercial Greenhouses (UMN Extension) Western Flower Thrips Feeding Scars and Tospovirus Lesions on Petunia Indicator Plants Agdia DAS ELISA and ImmunoStrip test
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Time: All year in greenhouse Hosts: Many flowering plants Thrips feeds on the flowers and foliage by inserting its modified left mandible into the tissue, and sucking the fluids from cells. Oviposition and feeding scars reduce the aesthetic quality and marketability of ornamental plants. These thrips spread tomato spotted wilt (TSWV) and impatiens necrotic spot viruses (INSV). Females lay eggs in tender plant tissue. The eggs hatch in 2 to 14 days, depending on temperature. Larvae are found in the protection of perianth of the flower or within developing terminal foliage. Late in the second instar they stop feeding and move down the plant to pupate. Thrips develop through two quiescent, non-feeding pupal stages in the soil, plant litter or in a protected area on the plant. Adults emerge and resume feeding on flowers, buds, and terminal foliage. The entire life cycle from oviposition to adult emergence can take 12 days in hot weather to 44 days in cool weather. Management: Rotate classes of insecticides to prevent resistance. Use blue or yellow sticky cards to monitor for adults.
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Greenhouse thrips References: Interiorscape Website (CUES)
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Time: All year in greenhouse Hosts: Many flowering plants Thrips feeds on the flowers and foliage by inserting its modified left mandible into the tissue, and sucking the fluids from cells. Oviposition and feeding scars reduce the aesthetic quality and marketability of ornamental plants. Greenhouse thrips move relatively slowly and rarely fly. They prefer a cool, shady, and fairly moist atmosphere. Reproduction is usually by parthenogenesis (laying unfertilized eggs). Under optimum conditions the time for development is 17 to 20 days for the eggs, about 13 days for the two larval instars, and about 5 days for the prepupal and pupal stages. The adults can live 7 weeks on plants growing in the greenhouse. Dark spots of excrement are often noticeable on the leaves and fruit. Pupae are found on leaves. Management: See western flower thrips. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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