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Pest: Broad mite

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Pest: Broad mite

 

 

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(Polyphagotarsonemus latus)

 

 

Special Species Notes

 

The broad mite is a microscopic species of mite, it's less than 1/2 the length of a grain of salt. You need a magnification of least 60 times to see them. It was first described by Banks (1904) as Tarsonemus latus from the terminal buds of mango in a greenhouse in Washington, D.C., USA

 

They are considered a very serious pest.  Losses of almost 100% have been reported. They are found in many areas throughout the world: Australia, Asia, Africa, North America, South America and the Pacific Islands. Countries included in this mite's distribution include American and Western Samoa, Bermuda, Brazil, China, Guyana, Fiji, India, Japan, Kiribati, Malaysia, Marianas, New Caledonia, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Taiwan, Tonga, Vanuatu, Wallis, and is present on all major Hawaiian Islands. The broad mite is considered a serious pest of Pittosporum spp. in Florida.

 

It has a worldwide distribution and is known by a number of common names. In India and Sri Lanka it is called the yellow tea mite, while those in Bangladesh call it the yellow jute mite. In some European countries it is called the broad spider. In parts of South America it is called the tropical mite or the broad rust mite.

 

The mites prefer areas of high humidity and low temperature. In the tropics and subtropics it reproduces the whole year round. In temperate climates it is a serious pest on vegetables in greenhouses. Due to its stupendous reproductive potential, it can reach damaging densities within a very short time. Moreover in some crops significant damage can occur at a very low infestation level.

 

 

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Identification

 

Female mites are about 0.2 mm long and oval in outline. Their bodies appear swollen and are a light yellow to yellow-brown to amber or green in color with an indistinct, light, median stripe that forks near the back end of the body. The two hind legs of the adult females are reduced to whip-like appendages.

 

Males are similar in color but lack the stripe. The body is short and oval. It is broadest at mid-length. The male is half the size of the females (0.11mm) and faster moving than the female. The legs are long and spindly are distinct and well defined. The male's enlarged hind legs are used to pick up the female nymph and place her at right angles to the male's body for later mating.

 

The eggs are colorless, translucent and elliptical in shape. They are about 0.08 mm long and are covered with 29 to 37 scattered white tufts on the upper surface. Eggs usually hatch in 2 to 3 days.

 

Larvae broad mites have only three pairs of legs. They are slow moving and appear whitish due to minute ridges on the body. As they grow they range in size from 0.1 to 0.2 mm long. The quiescent stage (pupal) appears as an immobile, engorged larva. The larvae feed for 1 to 3 days before going into the resting pupal stage.

 

The larva becomes a quiescent nymph that is clear and pointed at both ends. The nymphal stage lasts about a day. Nymphs are usually found in depressions on the fruit, although female nymphs are often carried about by males. The pupal stage of this mite is a resting period in which there is no feeding. Sexes are similar in appearance, except for the fourth pair of legs.The pupal lasts 2 to 3 days.

 

 

 

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Broad mite damage to pepper a few weeks after infestation.

Photograph by D. Riley, University of Georgia

 

 

Host plants:

 

Larvae and adults prefer to feed on the undersides of leaves usually in the vicinity of the egg.

 

The broad mite has a wide host range in tropical areas. It attacks greenhouse plants in temperate and subtropical regions. found on many species of plants, including important agricultural species such as apples, avocado, basil, beet, blackberry, cannabis, cantaloupe, castor, chili, citrus, cocoa,  coffee, cotton, cucumber, eggplant, grapes, guava, guava, jutes, jute, lemon, mandarin, mango, papaya, passion fruit, pear, potato, sesame, string or pole beans, tea, peppers, tomato, watermelon, African violet, ageratum, azalea, balsam, begonia, chrysanthemum, cruciferous crops, cyclamen, dahlia, daisy, gerbera, gloxinia, ivy, jasmine, impatiens, lantana, marigold, mulberry tree, peperomia, pittosporum, snapdragon, verbena, zinnia.

 

 

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First signs:

 

The damage resembles that caused by herbicide injury, PH imbalance, nutritional or physiological disorders. Mites are usually seen on shaded side of the newest leaves, buds, and small fruit or growing points. Broad mites puncture plant epidermis cells and suck out their contents, preferably on the young leaves, fruits. The sap loss and reduction in photosynthetically-active surface damage the plant.

 

A P. latus infestation can cause stunting and twisting of the leaves and flowers, and blackening and death of new growth. The changes induced by their feeding may persist for many weeks, therefore by the time the damage becomes apparent, the mites may already have disappeared.

 

 

Edges of damaged young leaves usually curl. Leaves turn downward and turn coppery or purplish. The foliage often becomes rigid and appears bronzed or scorched. As leaves age, they may split, producing a ragged appearance of different shapes. Internodes shorten and the lateral buds break more than normal. The blooms abort and plant growth is stunted when large populations are present.

 

 

Infested young potato leaves initially have oily black spots on the under surface, which later turn reddish. The plants become rosetted and then die back. Damage on cucumber, aubergines and Solanum laciniatum includes crinkling, cracking, discoloration and malformations similar to those caused by a hormonal weedkiller. When grapevine is attacked, young leaf edges turn downwards, followed by browning and necrosis. On fruit trees the damage is usually seen on the shaded side of the fruit, so it is not readily apparent. Fruit is discolored by feeding and in severe cases premature fruit drop may occur.

 

 

 

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Life cycle

 

Broad mites avoid direct sunlight and often hide in crevices, buds or other dark places.

Under optimal conditions temperatures:  69.8-80.6°F (21-27°C), and high relative humidity. P. latus can complete its life cycle in less than one week, 4 to 6 days. However, reproduction ceases at below 55.4°F (13°C) and above 89.6°F (34°C).

 

Adult females lay 30 to 76 eggs (averaging five per day) singly on the undersides of young leaves (near the veins), on flowers, or in depressions on fruits over an 8-13-day period and then die. Adult males may live 5-9 days. While unmated females lay eggs that become males, mated females usually lay four female eggs for every male egg.

 

The eggs hatch in two or three days and the larvae emerge from the egg to feed. Larvae are slow moving and do not disperse far. After two or three days, the larvae develop into a quiescent larval (nymph) stage. Quiescent female larvae become attractive to the males which pick them up and carry them to the new foliage. Males and females are very active, but the males apparently account for much of the dispersal of a broad mite population in their frenzy to carry the quiescent female larvae to new leaves. When females emerge from the quiescent stage, males immediately mate with them.

 

 

 

 

 

 

How it spreads:

 

broad mite use insect hosts, specifically some whiteflies, to move from plant to plant.

 

Mites are easily spread with tools, on clothing, or on the hands.

 

 

What to do

 

use the Integrated Pest Management (IPM) to discover infestations as early as possible, monitor regularly and carefully using a hand lens. The characteristic eggs are the only reliable criterion for distinguishing P. latus from other, mostly harmless tarsonemid mites.

 

Can be controlled by removing and destroying infested plants, and spraying with an acaricide.

 

Broad mites are very sensitive to heat, hot water treatment (45-50°C; 113 - 122°F for 15 minutes) of plants before they are transferred into a greenhouse may prevent the introduction of the pest.

 

 

Dusting with diatomaceous earth (for indoor or out) can help prevent pest invasions.

 

 

This mite is insusceptible to some chemicals, such as dinitrophenol compounds and synthetic pyrethroids.

 

Spraying with essential oil containing eucalyptol (eucalyptus and rosemary) can also help prevent insects from invading small growrooms.

 

Use miticides containing abamectin.

 

In Hawaii fenbutatin oxide (Vendex) and diazinon provide satisfactory control. Endosulfan provides superior control. Dicofol is effective, but may require a second application a week later in severe attacks.

 

Sulfur is effective but requires 2 -3 weeks to achieve control in some crops.

 

 

 

 

 

Biological control

 

Predatory mites

 

http://freemygreenpdx.com/topic/14451-beneficial-fungus-gnat-predators/

 

 

 

 

 

 

 

The link below will take you to "An Intro to beneficial bugs and beneficial insect food" it has a list (been worked on) to pests and beneficial insects

 

  http://freemygreenpdx.com/topic/14334-an-intro-to-beneficial-bugs-their-food-and-the-pest-they-take-care-of/

 


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