Insect Management

Dr. Kris Braman
Professor of Entomology
The University of Georgia

There are several types of insects that seem to like paspalum in particular, and left untreated, can cause significant damage. If you detect an insect infestation you will need to spray your seashore paspalum with an insecticide. Fortunately, there are a number of products that can be used for this. Once the insects are controlled, the grass will grow back.

Protection of pollinators:
Managed landscapes often contain flowering plants and can be important foraging sites for bees and other pollinators. Many insecticides are extremely toxic to bees, and others can affect colony health with repeated exposure. Use extreme care when applying insecticides to flowering plants, including turfgrasses. The neonicotinyl insecticides (IRAC group 4A) have systemic activity and can move to pollen and nectar if applied to plants in bloom. If there are flowering weeds, such as clover, in the turf, the blossoms should be mowed before application of this class of insecticide. Read and follow all restrictions on the labels, as there have been changes made recently to neonicotinyl use instructions.

Infestations of the following insects have been documented in seashore paspalum.

Fall army worm

Life Cycle
Females lay egg clusters on grass blades, other green plants, twigs, fences, sides of buildings, or any light colored object near turf. Eggs hatch in 7-10 days during cool weather and in 2-3 days during hot weather. Larvae mature in about 12 days during summer and 4 weeks during cool weather. Older larvae will pupate in the soil, and new moths will emerge in 9-20 days depending on temperature. Only 23-28 days required to complete a generation during mid-summer.

Feeding Symptoms
Scrap underside of leaf blades, leaving a clear upper skeletal epidermal layer; chew leaf margins, leaving a tattered look. Large larvae will eat all leaf material down to crown region.

Management
Spinosad (CONSERVE, IRAC Group 5) is an effective chemical control. Bt (Bacillus thuringiensis) may provide some control of small larvae (do not irrigate). Avoid mowing for at least 1-3 days after application of insecticides. Apply in the afternoon and avoid irrigating over night. Contact insecticides: acephate (ORTHENE, Group 1B), chlorpyrifos (DURSBAN, Group 1B), cyfluthrin (TEMPO),deltamethrin (DELTAGARD, Group 3A), trichlorfon (DYLOX Group 1B), carbaryl (SEVIN, Group 1B ), acelepryn (Group 28). Biorational products: entomopathogenic nematodes (Steinernema carpocapsae)–apply in early morning or late afternoon to avoid heat or direct sunlight. Irrigate to moisten soil and thatch; then again immediately after application, before spray droplets dry.

Billbugs

Life Cycle
Eggs are laid between leaf sheaths and hatch in 4-5 days. Young larvae burrow into grass stems, feeding and tunneling. Large larvae will burrow out and feed on the crown. 1-2 generations per year.

Feeding Symptoms
Stems turn straw colored and die in a scattered fashion. Can feed on roots, crowns, and stolons. Turf will easily pull up.

Management
Avoid stress-induced root or crown damage with sensible irrigation and fertilization.
Biological control—Fungus Beauveria and parasitic nematode (Steinernema carpocapsae)
Chemical control—Best strategy is Spring or early season pesticide application to target adults emerging from hibernation sites and prior to egg laying (soil surface temperature at one inch/25 mm depth = 67-69 F or 19.4-20.6 C). Systemic insecticides such as imidacloprid (MERIT) and clothianidin (ARENA, Group 4A) are effective if applied when adults become active and prior to egg hatching. Chlorantraniliprole (ACELEPRYN, GROUP 28) is also effective against caterpillars. Combination products imidacloprid +bifenthrin (ALLECTUS, Group 4A + 3A) and clothianidin + bifenthrin (ALOFT, GROUP 4A + 3A) are also available. Contact insecticides: chlorpyrifos (DURSBAN), bifenthrin (TALSTAR, Group 3A), carbaryl (SEVIN, Group 1A).

tropical sod webworm

Life Cycle
Life cycle: eggs hatch in about one week at 78 F (26 C). Larvae complete development in about 25 days.
Complete life cycle takes 5-6 weeks (78 F or 26 C) to 11 weeks (73 F or 23 C). Predominate damage is mid- to late summer.

Feeding Symptoms
Feed along midrib, between veins. Will chew notches in the leaf blades, giving a ragged appearance. Infested turf appears to be severely scalped, with large yellowish or brown patches.

Management
Spinosad (CONSERVE, IRAC Group 5) is an effective chemical control. Bt (Bacillus thuringiensis) may provide some control of small larvae (do not irrigate). Avoid mowing for at least 1-3 days after application of insecticides. Apply in the afternoon and avoid irrigating over night. Contact insecticides: acephate (ORTHENE, Group 1B), chlorpyrifos (DURSBAN, Group 1B), cyfluthrin (TEMPO),deltamethrin (DELTAGARD, Group 3A), trichlorfon (DYLOX Group 1B), carbaryl (SEVIN, Group 1B ), acelepryn (Group 28). Biorational products: entomopathogenic nematodes (Steinernema carpocapsae)–apply in early morning or late afternoon to avoid heat or direct sunlight. Irrigate to moisten soil and thatch; then again immediately after application, before spray droplets dry.

two-lined spittlebug

Life Cycle
Overwinter in thatch, behind leaf sheaths, or in stems. Eggs hatch as turf comes out of dormancy. Newly hatched nymphs seek moist, humid feeding sites near the base of grass plants. As they feed, they excrete a frothy spittle mass for protection from desiccation and enemies. Masses are found just below the soil surface (0-5 cm). Nymphs mature as adults in 34-60 days depending on moisture and temperature. Eggs hatch in 2-3 weeks during mid-summer. Generally 2 generations per year.

Feeding Symptoms
Adults and nymphs suck juice from the grass, weakening the plant. Adults inject a salivary toxin that is translocated up and down the stem, cause the whole plant to turn yellow and brown, then the grass dies. Sparse, blighted looking turf.

Management
Most abundant in years with high spring and summer rainfall. Damage resembles chinch bug feeding except that it occurs in shady areas rather than full sun. Young spittlebugs cannot survive under dry conditions and thrive in moist thatchy turf. Withhold irrigation when nymphs are hatching in the spring or midsummer. Dethatch and aerate to reduce spittlebug buildup.

Chemical control: Acephate (ORTHENE) and ,bifenthrin (TALSTAR, Group 3A), carbaryl (SEVIN, Group 1A), deltamethrin (DELTAGARD, GROUP 3A)

MOLE CRICKETS

Life Cycle
Spend most of their lives underground. When soil warms in the spring and nighttime temperatures reach 60 F (15 C), tunneling and feeding increase. Eggs are laid in chambers 4-12 inches (10-30 cm) below the surface. Parents die off after mating and egg-laying. Eggs take about 3 weeks to develop nymphs, which tunnel to the surface and feed in the upper soil and litter. Feed and burrow at night, just below the soil surface.

Feeding Symptoms
Root feeder. Uproots the plants, causing roots to dry out.

Management
chemical control is best during mid-summer when crickets and nymphs are small.

Chemical control: imidacloprid (MERIT, Group 4A) clothianidin (ARENA 4A) applied at the beginning of egg hatch, subsurface application of fipronil (CHIPCO CHOICE, Group 2B). Carbaryl bait (Group 1A). Apply late in afternoon to dry turf. Broadcast: chlorpyrifos (DURSBAN), lambdacyhalothrin (SCIMITAR, Group 3A), bifenthrin (TALSTAR, Group 3A)deltamethrin (DELTAGARD, Group 3A), acephate (ORTHENE, Group 1B).

Biological control: parasitic wasp—Larra bicolor parasitic nematodes—Steinernema

Bermudagrass mite

Life Cycle
Eggs hatch in 2-3 days. At 75 F (23.9 C), adulthood is reached in 7-10 days. Very tolerant of high summer temperatures. Prefer droughty conditions.

Feeding Symptoms
Feed underneath leaf sheaths. Grass appears weak and off color in the spring and does not respond to fertilization or irrigation. Yellowing of leaf tips and twisting of foliage. Shortening of stem internodes, resulting in tufted or rosetted growth (witches broom effect). Toxic saliva is injected into stems to cause stunting. Damage is worse in hot dry weather, especially in spring and fall.

Management
Irrigation to minimize drought stress.

Chemical control: Carbaryl may provide some suppression, no effective miticides are labeled

white grubs

Life Cycle
Larval stage of several species of scarab beetles. While most have one generation per year, some may require more than one year to complete their life cycle. The most common annual grubs spend about 2 weeks as eggs, 10 months as larvae, 2-3 weeks as pupae before becoming adults. Larvae overwinter, pupate in the Spring and emerge in early Summer.

Feeding Symptoms
Grubs feed on grass roots and organic matter. Infested turf may appear wilted and off color. Heavily infested turf may be easily lifted as the root system becomes severely pruned. Birds and mammalian predators may damage turf when they dig it up to feed on grubs.

Management
Vigorous turf may support as many as 20 grubs/Ft2 while stressed turf can be injured by 8-10 grubs/ Ft2. Successful management requires targeting the small (first and second instar) grubs.

Biological control: Several predators and parasitoids although none commercially available. Entomopathogenic nematodes Heterorhabditis bacteriophora can be effective when applied to moist soil when grubs are present – irrigate post application.

Chemical control: Carbaryl and pyrethroids are excellent for Green June beetle larvae only. Curative control of larger grubs requires trichlorfon (DYLOX, Group 1B). Systemic insecticides such as imidacloprid (MERIT) and clothianidin (ARENA, Group 4A) are effective if applied early in the life cycle. Chlorantraniliprole (ACELEPRYN, GROUP 28) is also effective against caterpillars. Combination products imidacloprid +bifenthrin (ALLECTUS, Group 4A + 3A) and clothianidin + bifenthrin (ALOFT, GROUP 4A + 3A) are also available.