Avocado Red Mite Oligonychus yothersi (Acari: Tetranychiidae), Avocado Bud Mite Tegolophus perseaflorae (K.) (Acari: Eriophyidae), Persea Mite Oligonychus perseae (Acari: Tetranychidae)
The avocado red mite is a common pest of avocados in Florida. The eggs are spherical and stalked. Adults have a pinkish color, with their middle area covered by many purplish-brown blotches. The duration of the life stages varies from 14 to 15 days. Females are capable of laying 40 to 50 eggs during their life span. The adult avocado bud mite has a yellowish appearance. Its life cycle has not been determined. Avocado bud mite populations begin to increase from March to May (Peña and Johnson, 1999).
Part of plant damaged: Leaves, buds
Avocado Red mite feeding is first confined to the upper surface of avocado leaves; it is found first along the midrib, then along secondary leaf veins. The areas along the veins become reddish-brown. During heavy infestations leaves can be covered with mite's cast skins. Damage to the leaf area is regularly observed from October through March, causing up to 30% reduction of photosynthetic activity of the leaves. Leaves affected by this mite regularly drop earlier (45-60 days after infestation) than those leaves that have not been infested. In Florida, the avocado bud mites were observed feeding on buds, causing necrotic spots on apical leaves, and subcircular, irregular openings on mature leaves. Mites were also found in petioles, the underside of leaves and fruitlets. This mite is also reported to feed on the peduncle, calyx and stylar area (Medina et al. 1978, Jeppson et al. 1975).
Monitoring and action levels
Mites are occasional pests in some orchards and are seldom observed in others. Periodic inspections are recommended during December, January and February. Control measures may be started when the population reaches 6 or more mites per leaf. Select 10 trees at random. Observe damage and mite densities using a hand lens. If higher damage is observed near borders or roads and not in the entire grove, apply control only to the first three rows. Young trees showing more than 60% bronzing to the leaf area the damage is uniform throughout the grove, apply control.
Few miticides are registered for use on avocados when fruit is present. Apply sulfur dust or spray with sulfur using 10 pounds of wettable sulfur per 100 gallons of water, or use oil emulsion sprays made by mixing 3 quarts of 90-92 percent oil concentrate per 100 gallons of water and apply thoroughly. Also see instructions on labels for various brands of oil. Pyrellin (pyrethrins + rotenone) is registered at 1 - 2 pts/A.
Peña, J. E., Duncan, R. E., Klema, E., Hunsberger, A. 1999. Evaluation of direct and indirect action of insecticides and acaricides for control of lime and avocado pests. Proc. Fla. State Hort. Soc. 112: 213-217.