Guava Trees & Spiders

The false spider mite can damage the guava fruit.

Often referred to as false spider mites, the Brevipalpus phoenicis and the Brevipalpus californicus mites can infest guava trees. Unchecked, the pests will cause considerable damage. Exceptionally small, the nearly immobile mites are difficult to detect with the naked eye. The Brevipalpus phoenicis mites, a vector of citrus leprosis virus and coffee ringspot virus, pose a significant risk to all susceptible tree species. The guava tree often functions as a host for the mite.

Appearance

The Brevipalpus phoenicis and the Brevipalpus californicus look physically similar to spider mites. Unlike actual spider mites, the pests do not spin webs. The body of the adult mite appears oval in shape, comes in shades of red or green and has eight distinct legs. The mites produce clusters of reddish-orange eggs that stand out in stark contrast on the tree's green foliage. The naked eye can make out the bright egg clusters. The larvae of the mites usually have a slightly transparent body. On close examination, the larva's internal organs become detectable as spots of green or tan that show through the insect's translucent skin.

Damage

The mite attaches its powerful mouth to the leaf, stem or fruit tissue of the guava tree, injects toxic saliva into the wound and sucks the guava tree's nutrients. Yellow spots form on the leaves where the mite feeds. The leaves eventually turn entirely brown, and the tree's new growth may appear deformed. The damaged foliage will begin to fall from the tree. The guava fruit may also split open or develop brown spotting from the feeding damage sustained from the mite. The tree's twigs usually show dieback if the mite infestation becomes severe.

Life Cycle

The mites have the capability of reproducing asexually. The eggs of the female mites do not require a male to guarantee fertilization, and more female mites occur than males. The mites require humid conditions to thrive. If the humidity falls below 30 percent, the mites cannot complete their life cycle, according to the University of Hawaii. They prefer temperatures that range from 68 to 86 degrees Fahrenheit. The mites' life span averages five to six weeks. During a female's life, she will produce 50 to 60 eggs, according to Bayer Cropscience. Gain control of the mites using miticides sprays.

Care

Maintain the guava tree's overall health to help it combat pest infestations. When planting the guava tree, Purdue University suggests spacing the trees at least 33 feet apart to allow them ample air circulation. The guava tree does not require extensive pruning; however, thinning during fruit production will help prevent the tree's branches from breaking and increase the size of the fruit. The guava tree benefits from frequent applications of fertilizer. It will also benefit from nutritional sprays that contain copper and zinc.

References

• Purdue University; Guava; J. Morton; 1987
• University of Florida Institute of Food and Agricultural Science: A False Spider Mite
• Bayer Cropscience; Brevipalpus Phoenicis
• University of Hawaii; Brevipalpus Phoenicis; Jayma L. Martin Kessing, et al.; August 1992

Resources

• University of Florida IFAS Extension; Guava Growing...; Jonathan H. Crane, et al.