Polyphagotarsonemus latus (Banks)
Taxonomic placing: Acari, Prostigmata, Heterostigmata, Tarsonemidae.
Common name: Broad mite; yellow tea mite; citrus silver mite; white mite.
Geographical distribution: Almost cosmopolitan. CIE Map #191, revised, 1986).
Host plants: Plants in about 60 families.
Morphology: Body of female oval, venter of metapodosoma with 3 pairs of coxal setae, legs long and slender, leg I with a strong claw. Male with a button-like claw on leg IV.
Life cycle: Eggs are usually deposited on the underside of young apical leaves, on which more than 100 eggs per cm² may be found. The eggs are greenish-white, ca 0.1 mm in length, elongate-oval in shape, and carry rows of whitish hollow tubercles. Emerging larvae feed for one day and molt. Males appear first and locate the pharate females (known as “diapausing larvae”, “pupae” or “quiescent nymphs”). The male places the pharate female on the terminal pad of its genital capsule and then moves upwards, to the plants’ apical parts (a movement that causes the pest’s populations to ascend to the apical parts of the host plant). Mating occurs shortly after female molt and each mated female deposits ca 40 eggs. Reproduction is arrhenotokous, unmated females producing only few male progeny, which live for one week under optimal conditions, females a few days more. The pest is most active in warm and wet seasons, as it prefers mild temperatures combined with very high humidities. A generation can be raised in a week at 25-30°C, and large pest populations may develop rapidly and unexpectedly. The pest has no diapause. Dry conditions have an adverse effect, and low (12-14°C) or high (33-35°C) temperatures are the lower and upper thresholds for the mite’s development is strongly female-biased (4:1), but may be lower under arid conditions, probably due to the susceptibility of immature females to lower humidities. In the field perennial crops as well as weeds serve as reservoirs for the pest. The quality of heavily attacked, susceptible plants deteriorates rapidly, in turn reducing mite populations.
Broad mite is dispersed by various means. Within infested plants pharate females are transported upwards by the males. Mites can arrive at suitable feeding sites by walking or borne on winds. Unmated females that arrive on new hosts can then mate with their sons and establish new colonies. Dispersal may be affected by various insects, especially various whiteflies (Hemiptera: Aleyrodidae), including the tobacco whitefly, Bemisia tabaci, which attracts P. latus by its wax flakes. The mite may be dispersed from area to area and from country to country through the transfer of infested plants.
Economic importance: Broad mite is a pest of ornamentals and vegetables under protected cultivation in temperate countries, attacking these and many perennial crops in the warmer parts of the world. On different plants its feeding causes a variety of symptoms; some of which were formerly believed to be caused by viruses. Feeding causes the foliage to curl, usually downwards, becoming bronzed and assuming a shriveled, scorched aspect, dark on potatoes, purple on cotton). Apical leaves are often heavily damaged, become distorted and may die, as do the buds. Flowers may drop and potato tubers show deep-seated splitting. Injured cucumber and tomato fruits are misshapen, russetted and cracked. On citrus broad mite damages mostly the yellow varieties, others are attacked only in greenhouses, occurring mostly on young leaves, in buds and on small fruits. Leaf blistering, crinkling, narrowing as well as various distortions may follow. Fruit reacts by developing silvery (on lemons and limes) or rust-colored (on oranges) blemishes with a “sharkskin” or corky texture that may extend over the entire surface, losing its commercial value. At times mite injury symptoms occur even after the pest had been eliminated, and/or at some distance from the feeding site. The symptoms may be intensified in detached fruits, resulting in injury being more evident in the market. In tropical and subtropical regions broad mite has been reported to cause 50% bean crop losses, to be a limiting factor for papayas and to be a serious pest of tea, pepper, egg plant, cotton, jute and various ornamentals. On some crops broad mite has become a major pest only quite recently. It is unclear whether this is due to the rise of more aggressive pest strains, to its exposure to more vulnerable plant varieties, to eliminating its natural enemies by pesticides, to its insensitivity to one group of widely used pesticides, the pyrethroids, or to any combinations of these factors.
Management
Sampling: Broad mite has a clumped distribution on its host plants, occurring mostly on their shaded parts on young leaves and the smaller fruits. On lime trees in Florida the pest was often concentrated in the middle canopy, and its numbers per cm2 fruit surface had a close relationship with the total number of mites present on such fruits. Thus an area of one cm2 fruit surface, taken from the middle tree stratum, would suffice for reliable sampling. In addition, due to the good fit between percentages of fruit surfaces damaged and percentages of fruit damage/tree, either could be used for estimating broad mite injury to lime. The aggregated occurrence of P. latus on lime fruit further facilitated sampling, as fewer fruits per orchard would be needed for an adequate estimate of its populations.
Plant resistance: The establishment and development of P. latus on various crop cultivars may be uneven, suggesting different degrees of susceptibility and thus the option of resistance. In solanaceous plants this may be due to the presence of trichomes) with sticky tips.
Chemical control: Many commonly-used acaricides provide satisfactory control, as do most organophosphates and avermectins. Selective lime sulfur concentrations, integrated with other management tactics, may provide sustainable control on chili pepper. Pyrethroids, on the other hand, are ineffective: broad mite outbreaks on cotton in Africa were attributed to the use of these pesticides against other pests, treatments which removed phytophagous competitors without affecting P. latus.
Biological control: No specific predators of broad mite are known, but several Phytoseiidae control the pest on various crops. In Israel Neoseiulus cucumeris controlled the pest on sweet pepper. In Turkey control on tea was obtained with Amblyseius swirskii and N. californicus (McGregor), and in Florida control on various crops was achieved with N. californicus and Neoseiulus barkeri Hughes.
References
Abou-Awad,B.A., Hafez, S.M. and Farahat, B.M. 2014. Biological studies of the predacious mite Amblyseius swirskii, a predator of the broad mite Polyphagotarsonemus latus on pepper plants (Acari: Phytoseiidae: Tarsonemidae). Archives of Phytopathology and Plant Protection 47: 349-354.
Abou-Awad,B.A., Hafez, S.M. and Farahat, B.M. 2014. Bionomics and control of the broad mite Polyphagotarsonemus latus (Banks) (Acari:Tarsonemidae). Archives of Phytopathology and Plant Protection 47: 631-641.
Abou-Awad,B.A., Hafez, S.M. and Farahat, B.M. 2014. Biological studies of the predacious mite Amblyseius swirskii, a predator of the broad mite Polyphagotarsonemus latus on pepper plants (Acari: Phytoseiidae: Tarsonemidae). Archives of Phytopathology and Plant Protection 47: 349-354.
Akyazi, R., Sekban, R., Soysal,M., Akyol, D., Colee, J. and Saim Bostan, S.Z. 2018. Ecofriendly control approaches for Polyphagotarsonemus latus (Acari: Tarsonemidae) on tea (Camellia sinensis L.). International Journal of Acarology (in press).
Fan, Y. and Petitt, F.L. 1994. Biological control of broad mite, Polyphagotarsonemus latus (Banks), by Neoseiulus barkeri Hughes on pepper. Biological Control 4: 390-395.
Gerson, U. 1992. Biology and control of the broad mite Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae). Experimental and Applied Acarology 13: 163-178.
Jones, V.P. and Brown, R.D. 1983. Reproductive responses of the broad mite, Polyphagotarsonemus latus (Acari: Tarsonemidae), to constant temperature-humidity regimes. Annals of the Entomological Society of America 76: 466-469.
Palevsky, E., Soroker, V., Weintraub, P., Mansour, F., Abu-Moach, F. and Gerson, U. 2001. How species-specific is the phoretic relationship between the broad mite, Polyphagotarsonemus latus (Acari: Tarsonemidae), and its insect hosts? Experimental and Applied Acarology 25: 217-224.
Peña, J.E. and Baranowski, R.M. 1990. Dispersion indices and sampling plans for the broad mite (Acari: Tarsonemidae) and the citrus rust mite (Acari: Eriophyidae) on limes. Environmental Entomology 19: 378-382.
Peña, J.E. and Osborne, L. 1996. Biological control of Polyphagotarsonemus latus (Acarina: Tarsonemidae) in greenhouses and field trials using introductions of predaceous mites (Acarina: Phytoseiidae). Entomophaga 41: 279-285.
Soroker, V., Nelson, D.R., Bahar, O., Reneh, S., Yablonski, S. and Palevsky, E. 2003. Whitefly wax as a cue for phoresy in the broad mite, Polyphagotarsonemus latus (Acari: Tarsonemidae). Chemoecology 13 163-168.
Vaissayre, M. 1986. Chemical control of the mite Polyphagotarsonemus latus (Banks) in cotton fields. Coton Fibres Tropicales 41: 38-43.
van Maanen, R., Vila, E., Sabelis, M.W. and Janssen, A. 2010. Biological control of broad mites (Polyphagotarsonemus latus) with the generalist predator Amblyseius swirskii. Experimental and Applied Acarology 52: 29–34.
Venzon, M., Oliveira, R.M., Perez, A.L., Rodrıguez-Cruz, F.A. and Martins Filho, S. 2013. Lime sulfur toxicity to broad mite, to its host plants and to natural enemies. Pest Management Science 69:738–743.
Weintraub, P.G., Kleitman, S., Mori, R., Shapira, N. and Palevsky, E. 2003. Control of the broad mite (Polyphagotarsonemus latus (Banks)) on organic greenhouse sweet peppers (Capsicum annuum L.) with the predatory mite, Neoseiulus cucumeris (Oudemans). Biological Control 27: 300–309.