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Mites on Ornamental Plants 1
D. E. Short and E. A. Buss2Spider mites ( Figure 1 ) are among the most common pests which attack ornamental plants in Florida. They are not insects, but more closely related to spiders and ticks. Adult mites, spiders and ticks have eight legs. Mature mites are usually less than 1/50 inch in length and generally found on the undersides of the leaves. Mite infestations are often not detected until the plants are severely damaged.
Mites have needle-like, piercing mouthparts with which they puncture the leaf and suck the plant juices. Damage from light infestations appears as yellow or gray stippled patterns on the leaves. The undersides of infested leaves usually have fine silken webbing spun across them (Figure 2). Heavy infestations cause the leaves to turn yellow, gray or brownish and eventually drop off. Webbing may be spun over entire branches or in the case of small plants, over the entire plant. Examine the undersides of the leaves for mites using a 10 or 15 power magnifying glass. Mites can be seen more easily by shaking the foliage over a white sheet of paper and observing any mites present. They may be reddish, green, yellow, purple, black or virtually colorless. The body contents sometimes show through their transparent body wall giving them a spotted appearance. Cast skins may also be seen among the live mites imparting a grayish residue to the undersides of the leaves. There are many species of mites and their development differs somewhat, but a typical life cycle is as follows. The adult female mite is capable of laying several hundred eggs during her life. The eggs are attached to the fine silk webbing and hatch in approximately three days. The immature mites molt three times before reaching the adult stage. The length of time from egg to adult stages varies greatly depending on temperature. Under optimum conditions, (approximately 80 degrees F), mites complete their development from egg to adult in 7 to 10 days. There are many overlapping generations per year.
CREDITS: University of Florida
Figure 1. Two-spotted spider mite.
CREDITS: Lyle Buss, University of Florida
Figure 2. Two-spotted spider mite webbing on strawberries. Some of the plants on which mites are frequently found include african violet, azalea, camellia, chrysanthemum, citrus, eleagnus, holly, ligustrum, pyracantha, orchid, rose and viburnum as well as others. Mite damage is much more severe during dry weather. Large numbers of mites are commonly seen during the spring months, especially April and May, and also again in September and October.
Control of Mites
Many homeowners can remove mites and keep populations below damaging levels by spraying their landscape plants with a forceful stream of water. Use a garden hose with an adjustable nozzle and spray undersides of leaves when mites appear.One of the most important aids in successful mite control is to begin treatments before damage becomes severe. Inspect your plants frequently with the aid of a magnifying glass and treat promptly when damage begins to become evident (See Table 1 ). Two applications 5 to 6 days apart are required for satisfactory control. Spray the plants to the point of run off. Be especially careful to spray the undersides of the leaves thoroughly. Continue to inspect your plants throughout the year and apply a miticide again if needed followed with a second application 5 to 6 days later. Soil treatments are relatively slow in action but are effective for long periods of time (usually five to six weeks). See Table 1.
Beneficial Mites and Insects
Insect predators including lady beetles, praying mantis, assassin bugs and tiny parasitic wasps prey upon harmful mites. Many mite species are actually predators, and do not damage plants. Every effort should be made not to destroy these beneficial organisms. Do not apply an insecticide unless plant damage is becoming evident.
Tables
Table 1. Miticides labeled for use by professional applicators in residential areas or interiorscapes.
Brand Name
Active Ingredient
Chemical Class
Use Sites1
Target Pests
Avid Abamectin Macrocyclic Lactone L Broad, cyclamen, eriophyid and spider mites Cinnamite Cinnamaldehyde Cinnamon oil F, H, L, V Mites Conserve Spinosad Naturalyte L, T Spider mites DeltaGard Deltamethrin Pyrethroid L Mites (suppression) Floramite Bifenazate Carboxamide IN, L Spider mites Hexygon Hexythiazox Carbazate IN, L Spider mites Horticultural Oils Paraffinic oil Oil F, IN, L, V
Spider mites and eriophyid mites Insecticidal Soaps Potassium salts of fatty acids Soap F, H, IN, L, V
Spider mites Kelthane Dicofol Organochlorine F, L, T, V
Broad, cyclamen, and spider mites Sanmite Pyridaben Pyrazole L Broad and spider mites Scimitar Lambda-cyhalothrin Pyrethroid IN, L, T Broad and spider mites Shuttle Acequinocyl Naphthoqinone derivative
L Spider mites Sulfur Elemental sulfur Inorganic F, L, V Broad and spider mites Talstar Bifenthrin Pyrethroid IN, L, T Mites Triact Neem oil Botanical IN, L, T Mites Vendex Fenbutatin-oxide Organotin L Spider mites 1 Key for use sites: IN-interiorscape T-turf L-landscape ornamentals F-fruit V-vegetables H-herbs
Footnotes
1. This document is ENY-319, one of a series of the Department of Entomology and Nematology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First Published: October 1993. Date Revised: June 2005. Please visit the EDIS Web site at http://edis.ifas.ufl.edu.2. D. E. Short, retired professor-extension entomologist and E. A. Buss, assistant professor, Department of Entomology and Nematology, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.
U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean.
Copyright Information
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