|Geographic distribution of T. palmi (green) and eradicated (light green)|
Melon thrips (Thrips palmi) is an insect from the Thrips genus. It is a primary vector of plant viruses. T. palmi can cause damage to a wide range of glasshouse ornamental and vegetable crops, particularly plants in the families Cucurbitaceae and Solanaceae, such as cucumber, aubergine, tomato and sweet pepper.
Symptoms[edit | edit source]
Adults and nymphs feed by sucking the cell contents from leaves, stems, flowers and the surface of fruits, thereby causing silvery scars, and leaf chlorosis. Plant growth can be deformed and heavily scarred. A severe infestation can kill the entire plant.
Control[edit | edit source]
Cultural control[edit | edit source]
Several cultural practices apparently affect melon thrips abundance, but few have been evaluated in the context of North American agriculture. Physical barriers such as fine mesh and row cover material can be used to restrict entry by thrips into greenhouses, and to reduce the rate of thrips settling on plants in the field.
Organic mulch is thought to interfere with the colonization of crops by winged thrips. Plastic mulch also is reported to limit population growth, but it is uncertain whether this is due to reduced rates of invasion or denial of suitable pupation sites.
Heavy rainfall is thought to decrease thrips numbers. However, there seems to be no evidence that overhead irrigation is an important factor in survival.
Resistance[edit | edit source]
Susceptibility to injury varied among pepper cultivars. Although sweet and jalapeno types were sensitive to foliar injury, cubanelle and cayenne types produced acceptable size and quality fruit. This is the reverse of injury susceptibility to western flower thrips, so in areas with mixed thrips populations growers cannot rely solely on plant selection to avoid damage.
Biological control[edit | edit source]
The predatory mite Neoseiulus cucumeris has been investigated for suppression of melon thrips. The mite density is correlated with thrips density, but within-plant distribution differs among the two species, suggesting that although the mites may increase in numerical abundance they are unlikely to drive the thrips to extinction.
Chemical control[edit | edit source]
Foliar insecticides are frequently applied for thrips suppression, but at times it has been difficult to attain effective suppression. Various foliar and drench treatments, alone or combined with oil, have achieved some success though it is usually inadvisable to apply insecticides if predators are present. The eggs, which occur in the foliar tissue, and the pupae, which reside in the soil, are relatively insensitive to insecticide application.
Gallery[edit | edit source]
References[edit | edit source]
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- ↑ a b c UF/IFAS Featured Creature article on Thrips palmi, melon thrips
- ↑ a b c d e f Capinera, J.L. (2010). Thrips palmi Karny (Insecta: Thysanoptera: Thripidae). University of Florida Institute of Food and Agricultural Sciences. Retrieved: 2011-02-13.
- ↑ Etienne J, Guyot J, van Waetermeulen X. 1990. Effect of insecticides, predation, and precipitation on populations of Thrips palmi on aubergine (eggplant) in Guadeloupe. Florida Entomologist 73: 339-342.
- ↑ Nuessly GS, Nagata RT. 1995. Pepper varietal response to thrips feeding. Pages 115-118 In Parker BL, Skinner M, Lewis T (eds.), Thrips Biology and Management. Plenum Press, New York.
- ↑ Castineiras A, Baranowski RM, Glenn H. 1997. Distribution of Neoseiulus cucumeris (Acarina: Phytoseiidae) and its prey, Thrips palmi (Thysanoptera: Thripidae) within eggplants in south Florida. Florida Entomologist 80: 211-217.
- ↑ Seal DR, Baranowski RM, Bishop JD. 1993. Effectiveness of insecticides in controlling Thrips palmi Karny (Thysanoptera: Thripidae) on different vegetable crops in south Florida. Proceedings of the Florida State Horticultural Society 106: 228-233.
- ↑ Seal DR. 1994. Field studies in controlling melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae) on vegetable crops using insecticides. Proceedings of the Florida State Horticultural Society 107: 159-162.