SP127 Turfgrass Insects Sheet 2 1 D.E. Short and J.L. Castner2 1. This document is SP127, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date November 1992. Reviewed May 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 2. D.E. Short, Professor; J.L. Castner, Scientific Photographer; Department of Entomology and Nematology, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611. The term plates, where used in this document, refers to color photographs that can be displayed on screen from the FAIRS CD-ROM. These photographs are not included in the printed document. 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. 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 White grubs. Five genera of grubs may infest any of our turfgrasses. The masked chafers, Cyclocephala spp. (Plate 1) are the most common, but Phyllophaga spp., Bothynis spp., Strategus spp. and Ataenius spp. are also in Florida. These pests are the larval stage of beetles such as May or June beetles. The eggs are laid in the soil usually during May or June, one to two inches below the soil surface. The grubs feed on grass roots and remain in this stage for one to four years, depending on the species. They are white with a brown head, three pairs of small legs, and are C-shaped. In infested areas the grass consistently wilts, and mosaic areas of yellow and green grass develop (Plate 3). To check for grubs, cut three sides of a one-foot-square piece of sod about two inches deep at the edge of one of the off-color areas (Plate 2). See if the grass roots are chewed off and sift through the soil looking for the larvae. Check several other places. If you find an average of three to five grubs per square foot, control is justified. Hunting billbugs, Sphenophorus venatus vestitus (Plate 4). This insect sometimes causes injury to turf in Florida, especially to zoysia grass and Bermuda grass (Plate 5). The adult beetle has a bill or snout, is black, and is about 1/2" long. Beetles lay their eggs inside the grass stem at about the soil line. The larvae hatch in one week and feed for several weeks inside the stems of the grass, then migrate to the roots. The larva, or grub, is white with a brown head, legless and about 3/8" long when mature. Damage usually first appears as yellow spots only a few inches in diameter. These areas gradually become larger and the turf has a spotted or mosaic appearance. Check for billbugs as described for grubs. If you find 10 larvae per square foot, apply an insecticide. Twolined spittlebugs, Prosapia bicincta (Plate 6). Adults are 1/4" long, and black with two reddish-orange, transverse bands on the wings. Eggs are laid in the thatch. The nymphs are white and live within a mass of frothy "spittle" they secrete on the grass (Plate 7). The life cycle requires two and one-half months and there are two generations per year. Both adults and nymphs withdraw plant sap with their piercing-sucking mouthparts. Damaged grass tips are yellowish, and eventually curl and turn brown.
Turfgrass Insects Sheet 2 2 Banks grass mite, Oligonychus pratensis. In Florida, this mite has become an occasional pest of St. Augustinegrass. These spider mites are less than 1/50" and green. The mite's color and small size make it difficult to detect. The length of their life cycle varies from eight to 25 days, depending on the temperature. Damage appears as leaf stippling that turns yellow (Plate 8). Damage is more severe during dry periods. Bermudagrass mite, Eriophyes cynodoniensis. The Bermudagrass mite is sometimes a pest of Bermuda grass throughout Florida. The most severe damage occurs to the coarser varieties such as Common and Ormond (Plate 9). The mites are only about 1/130", yellowish-white, and somewhat wormlike in shape. Their life cycle is complete in seven days. The mite causes a characteristic type of damage: the grass blades turn light-green and curl abnormally. The internodes shorten and tissues swell. The grass becomes tufted and thins out. Injury is more pronounced during dry weather, especially when the grass is stressed. The mites prefer taller grass, such as that growing along fence rows. Imported fire ant, Solenopsis invicta. The red imported fire ant is a small, aggressive ant that builds a rounded, conical nest, or mound, often two or three feet across (Plate 10). The fire ant was imported in about 1940, and since then has spread widely. All counties in Florida are infested. The ants are 1/8" to 1/4" long and reddish-brown to black. These social insects live in colonies, which may have up to 200,000 individuals. The imported fire ant sting is a painful burning. It causes pustules that may take up to 10 days to heal. If broken, a pustule may become infected. Some people have an allergic reaction to fire ant stings. A few have died as a result of allergic responses to the stings, but this is very rare.