Bugs for Growers — Turfgrass

Chinch bugs: one the most severe pests of turf foliage

How to identify Chinch bugs?

Chinch bugs are true bugs as they have piercing and sucking type of mouthparts i.e. long slender beak used for sucking cell sap from grass leaves. Young stages of chinch bug are called nymphs. Newly hatched nymphs are yellow in color but their color or body markings changes from yellow to reddish-black to orange-black as they molt from one stage to other stage during development. Also, with each molt nymphs more closely look like the adults. Chinch bug adults are about 1/6 inch long, and black and white in color.

Life cycle of chinch bugs:

Chinch bugs develop through three different stages: Egg, nymph and adult. These bugs over-winter as adults in protected areas such as under shrubs, in leaf litter and thick thatch layers. In the spring, the overwintering Chinch bug adults resume feeding on new turfgrass growth and at the same time start mating. After mating, females begin laying eggs. During a life span of usually 40 to 50 days, each female lay over 300 eggs on the grass leaves or stems near the ground. Under optimal environmental temperatures, eggs hatch within 7-15 days. Immediately after hatching from eggs, chinch bug nymphs start feeding on grass foliage. While feeding on grass over the period of 4 to 6 weeks, nymphs molts (shed its cuticle) 5 times, and go through 5 stages (instars) of development and become adults (6^th stage). These adults begin mating and start laying eggs from July through August. Then as stated above, after hatching from eggs, the second generation nymphs feed through October and go though different stages of growth, and become adults, which are ready for overwintering when cool temperature sets in.

Damaging stages of chinch bugs:

All six nymphal stages of chinch bugs cause damage to grass or other host plants. Adult chinch bugs also cause serious damage to grasses.

How chinch bugs cause damage to turf?

All the stages including adults of chinch bugs feed on a variety of grasses such as bentgrass, Kentucky bluegrass, perennial ryegrass, and red fescues. Both adult and nymphs of chinch bugs cause damage by sucking cell sap with their long slender beak from grass leaves.  While feeding they also inject toxins into grass leaves that causes clogging of leaf vascular system and affecting translocation of water and nutrients.  In case of severe infestation of chinch bugs, irregular brown patches of dead grass are noticed in the sunny areas of lawns.

Biological control of chinch bugs:

Natural enemies such as ants, big eyed bugs (Geocoris uliginosus), earwigs, ground beetles (see photo below), spiders, red imported fire ants (Solenopsis invicta) and wasps (Eumicrosoma benefica) help to suppress the populations of chinch bugs.  Entomopathogenic nematodes (Steinernema carpocapsae) and fungi (Metarhizium anisopliae and Beauveria bassiana) have a potential to manage chinch bugs. [caption id="attachment_257" align="alignright" width="300" caption="Ground beetles are natural enemies of chinch bugs"][/caption]

What stages of chinch bugs can be attacked by natural enemies?

Entomopathogenic nematodes can attack both adults and nymphal stages whereas entomopathogenic fungi can attack all the life stages including eggs of chinch bugs.  Also, predatory big eyed bugs can feed on all the stages of chinch bugs.

Buy Steinernema carpocapsae Nematodes

Literature:

Baxendale, F.P., A.P. Weinhold, and T.P. Riordan. 1994. Control of Buffalograss chinch bugs with Beauvaria bassiana and entomopathogenic nematodes, 1993. Nebraska insect management and insecticide efficacy reports, Dept. of Entomology Report No. 18, Univ. of Nebr., p. 43. Carstens, J.D., Baxendale, F.P., Heng-Moss, T. M. and Wright, R.J. 2008. Predation of the Chinch Bug, Blissus occiduus Barber (Hemiptera: Blissidae) by Geocoris uliginosus (Say) (Hemiptera: Lygaeidae). Journal of the Kansas Entomological Society 81: 328-338. Cherry, R. 2001.  Interrelationship of ants (Hymenoptera : Formicidae) and southern chinch bugs (Hemiptera : Lygaeidae) in Florida lawns.  Journal of Entomological Science 36: 411-415. Cherry, R. 2005. Interrelationship of big-eyed bugs (Hemiptera: Lygaeidae) and southern chinch bugs (Hemiptera : Lygaeidae) in Florida lawns. Journal of Entomological Science 40: 385-389. Samuels, R.I. and Coracini, D.L.A. 2004. Selection of Beauveria bassiana and Metarhizium anisopliae isolates for the control of Blissus antillus (Hemiptera: Lygaeidae). Scientia Agricola 61: 271-275. Samuels, R.I., Coracini, D.L.A., dos Santos, C.A.M. and Gava, C.A.T. 2002.  Infection of Blissus antillus (Hemiptera: Lygaeidae) eggs by the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana.  Biological Control 23: 269-273.

Sod webworms: One of the most damaging pests of turfgrass foliage

How to identify Sod webworms?

Full grown larvae/caterpillars of sod webworms are easy to identify as they are about 1 inch long having 4 parallel rows of distinct dark spots along the length of their body and coarse hair distributed all over the body. Also, depending upon species, caterpillars can be gray, brown or greenish in color. Adult sod webworm moths are light, brown or dull ash gray in color.

Life cycle of sod webworms:

Sod webworms develop through four different stages including egg, caterpillar/larva, pupa and adult moth. Sod webworms over-winter as caterpillar in silk-lined tunnels prepared in thatch and/or soil. In the spring, overwintering caterpillars resume feeding on new turfgrass growth, while feeding molts (shed its cuticle) 5-9 times and go through 6-10 stages (instars) of development. Last instar larva pupates inside the cocoons built from soil particles and plant debris in May through June. After 10-15 days of pupation, adult moths emerge from pupae and begin mating. After mating, female moths generally start laying their eggs individually while they are flying and dropping them randomly into the grass. Each moth lays up to 500 eggs during a life span of usually 10 to 15 days. Under optimal environmental temperatures, eggs hatch within 7-15 days. After hatching from egg, larval stage starts immediately feeding on grass foliage. These second generation caterpillars of sod webworms feed through September then overwinter and life cycle continues.

Damaging stages of sod webworms:

All six – ten stages/ instars of sod webworm caterpillars also called larvae cause damage to different grass species or other host plants. Adult moths do not cause any type of damage to any grass species.

How damage is caused?

All the stages of sod webworm caterpillars feed on a variety of grasses. Caterpillars generally chew leaves and stems at the crown of turfgrass causing thinning of grass in small areas. As the infestation progresses, these damaged small areas turn into large brown patches.  When infestation of sod webworms is very high, the damage caused by them is easily noticed as large and irregular brown patches are seen throughout lawns or golf course.  Sod webworm caterpillars feed at night but hide in the silk-lined tunnels prepared by them in thatch and/or soil during day time. The presence of irregular brown patches of dead grass caused by feeding of sod webworm in the middle of a lawn or golf course can reduce its aesthetic value.

Biological control of sod webworms:

Biological control agents including Bacillus thuringiensis (a bacterium which produces a toxin and paralyzes the gut of the caterpillar) and entomopathogenic nematodes also recognized as beneficial nematodes have a potential to manage sod webworms. However, beneficial nematodes have showed promising results in controlling sod webworms.

Why we should use beneficial nematodes?

Beneficial nematodes can kill sod webworm caterpillar with 48 hours after application. They are commercially available and easy to apply. Beneficial nematodes are not harmful to children, dogs, cats, personnel involved in its application and beneficial insects like honeybees. Beneficial nematodes do not need a special permission to apply because they are exempted by EPA.

Which species of beneficial nematodes are effective against sod webworms (see literature below)?

• Steinernema carpocapsae
• Heterorhabdtis bacteriophora

 What stages of Sod webworms can be targeted?

All the stages of caterpillars/ larvae and pupae can be targeted because both larvae and pupae are susceptible to beneficial nematodes. 

What is a recommended rate of beneficial nematodes required to control sod webworms?

For the successful control most of the soil dwelling insect pests, the optimal rate of 1 billion infective juveniles of beneficial nematodes in 100 to 260 gallons of water per acre is generally recommended (See Table for appropriate amounts of nematodes required for different sizes of sod webworm infested areas to be treated).

Where you can buy beneficial nematodes?

• Both Steinernema carpocapsae and Heterorhabdtis bacteriophora nematodes are sold in our store.
• Steinernema carpocapsae nematodes available both in liquid (sponge-water suspension) and granulated formulations
• Heterorhabdtis bacteriophora nematodes available only in liquid (sponge- water suspension) formulations

How long it takes to deliver nematodes?

We can directly deliver beneficial nematodes at your facility in person (service available only in Athens,Georgia) or by UPS throughout US within 3 days after receiving order.

When to apply beneficial nematodes

• To target sod webworms, beneficial nematodes should be applied starting from early spring through late summer i.e. when young larval (caterpillars) stages (instars) of sod webworms are already hatched from eggs and started feeding on grass leaves.
• Since nematodes are very sensitive to UV light, they will die within a minute or two when exposed to full sun. Therefore, nematodes should be applied early in the morning or late in the evening to avoid exposure to UV light.
• Another advantage of applying nematodes late in the evening is that sod webworm caterpillars can be easily targeted because they are generally active and searching for food during night and easily found by Steinernema carpocapsae nematodes that uses sit and wait (ambush) strategy to attack its passing by host.  Since sod webworm caterpillars are moving actively during night in search of food, they can easily come across to Heterorhabdits bacteriophora nematodes that uses cruising strategy to finds its host. Heterorhabdits bacteriophora nematodes can also find caterpillars that are hiding under thatch during day time.

How beneficial nematodes kill sod webworms?

After application of either Steinernema spp. or Heterorhabditis spp. on the lawns, their their infective juveniles find sod webworm larva or pupa and enter into its body cavity through natural openings such as mouth, anus and spiracles. Once infective juveniles of both Steinernema spp. and Heterorhabditis spp are in the insect body cavity, they release several cells of symbiotic bacteria, Xenorhabdus spp. and Photorhabdus spp., respectively from their gut via anus in the sod webworm blood, which is conducive for the multiplication of symbiotic bacteria. In the blood, multiplying nematode-bacterium complex causes septicemia and kill sod webworm caterpillar also called larvae usually within 48 h after infection.

Literature:

Grewal, P.S. Koppenhofer, A.M. and Choo, H.Y. 2005. Lawn, turfgrass and pasture applications. In: Nematodes As Biocontrol Agents. Grewal, P.S. Ehlers, R.-U., Shapiro-Ilan, D. (eds.). CAB publishing, CAB International, Oxon. Pp 115-146.

Armyworms: The important insect pest of turfgrass foliage

How to identify armyworms?

Armyworms are easy to identify. Adult moths are light reddish brown in color whereas their full grown larvae/caterpillars are brown in color and having several stripes on their body, and a distinctive "Y" shape mark on the head.

• [caption id="attachment_184" align="alignnone" width="293" caption="Adult armyworm moth"][/caption]

[caption id="attachment_217" align="alignnone" width="252" caption="A full grown caterpillar or larva of armyworm"][/caption]

Life cycle of armyworms:

Armyworms develop through four different stages: Moth, egg, caterpillar (larva) and pupa. Adult moths of armyworm begin emerging from over-wintering pupae early June through early August and start mating. After mating, each female moth lays about 500 eggs in a cluster on the lower surface of the leaves. Under optimal environmental conditions, eggs hatch within one week. After hatching from egg, larval stages starts feeding on grass foliage. While feeding, larvae molts (shed its cuticle) five times, and go through six stages (instars) of development. In the late summer mature, larva falls off the leaves and burrow into ground to form pupa, which survive during winter and life cycle continues. 

Damaging stages of armyworms:

• All the six stages/ instars of caterpillars/larvae of armyworms cause damage to grass or other host plants.
• Adult moths do not cause any type of damage to grasses or other plants.

  [caption id="attachment_213" align="alignnone" width="300" caption="Armyworm caterpillars or larvae cause a serious damage to the foliage of several grass species"][/caption]

How damage is caused?

All the larval stages cause damage by chewing margins of leaves of all kinds of grasses during night but hide under thatch during day time. Under sever infestation, caterpillars can skeletonize turf plant and reduce the aesthetic value of turfgrass.

Biological control of armyworms:

• Biological control agents including Nucleopolyhedrovirus, parasitoids (Braconid wasps, Apanteles spp. and Tachinid flies) and entomopathogenic nematodes have a potential to manage armyworms.

Why we should use entomopathoegnic nematodes?

• They can kill armyworm larvae with 48 hours after application.
• They are commercially available and easy to apply.
• They are not harmful to children, dogs, cats, personnel involved in its application and beneficial insects like honeybees.
• They do not need a special permission to apply because they are exempted by EPA.

Which species of entomopathogenic nematodes are effective against Armyworms (see literature below)?

• Steinernema carpocapsae
• Heterorhabdtis indica
• Heterorhabdtis bacteriophora

 What stages of armyworms can be targeted?

All the six stages of caterpillars/ larvae are susceptible to entomopathogenic nematodes. Pupae are also susceptible to entomopathogenic nematodes.

What is a recommended dosage of entomopathogenic nematodes required to control armyworms?

•  For the successful control of most of the soil dwelling insect pests, the optimal rate of 1 billion infective juvenile nematodes in 100 to 260 gallons of water per acre is generally recommended (See Table1).

Where you can buy entomopathogenic nematodes?

• All three entomopathogenic nematodes including Steinernema carpocapsae, Heterorhabdtis bacteriophora and Heterorhabdtis indica are sold in our store.
• Steinernema carpocapsae nematodes available both in liquid (sponge-water suspension) and granulated formulations.
• Heterorhabdtis indica and Heterorhabdtis bacteriophora nematodes available only in liquid (sponge- water suspension) formulations.

How long it takes to deliver nematodes?

We can directly deliver entomopathogenic nematodes at your facility in person (service available only in Athens,Georgia) or by UPS throughout US within 3 days after receiving order.

When to apply nematodes

• To target armyworms caterpillars, entomopathogenic nematodes should be applied starting from late June through late August i.e. when young larval (caterpillars) stages (instars) of armyworms are already hatched from eggs (laid in early June) and started feeding on grass leaves.
• To target especially armyworm pupae (to suppress the armyworm moth emergence in the next spring), entomopathogenic nematodes should be applied in late summer when caterpillars starting to fall off from leaves on the ground for pupation.
• Since nematodes are very sensitive to UV light, they will die within a minute or two when exposed to full sun. Therefore, nematodes should be applied early in the morning or late in the evening to avoid exposure to UV light.
• Another advantage of applying nematodes late in the evening is that armyworm caterpillars can be easily targeted because they are generally active and searching for food during night and easily found by entomopathogenic nematodes like Steinernema carpocapsae that uses sit and wait (ambush) strategy to attack its passing by host.  Since armyworm caterpillars are moving actively during night in search of food, they can easily come across to entomopathogenic nematodes like Heterorhabdits bacteriophora and Heterorhabdits indica that uses cruising strategy to finds its host. Because of cruising strategy, both Heterorhabdits bacteriophora and Heterorhabdits indica nematodes can also find caterpillars that are hiding under thatch during day time.

How entomopathogenic nematodes kill armyworms?

After application of either Steinernema spp. or Heterorhabditis spp. on the lawns, their their infective juveniles find armyworm larva or pupa and enter into its body cavity through natural openings such as mouth, anus and spiracles. Once infective juveniles of both Steinernema spp. and Heterorhabditis spp are in the insect body cavity, they release several cells of symbiotic bacteria, Xenorhabdus spp. and Photorhabdus spp., respectively from their gut via anus in the insect blood. Insect blood is conducive for the multiplication of symbiotic bacteria. In the blood, multiplying nematode-bacterium complex causes septicemia and kill their insect host usually within 48 h after infection.

Literature:

• Andalo, V., Santos, V., Moreira, G.F., Moreira, C., Freire, M. and Moino, A. 2012.   Movement of Heterorhabditis amazonensis and Steinernema arenarium in search of corn fall armyworm larvae in artificial conditions.  Scientia Agricola 69: 226-230.
• Ansari, M.A., Waeyenberge, L. and Moens, M. 2007.  Natural occurrence of Steinernema carpocapsae, Weiser, 1955 (Rhabditida: Steinernematidae) in Belgian turf and its virulence to Spodoptera exigua (Lepidoptera: Noctuidae). Russian Journal of Nematology 15: 21-24.
• Kim, J. and Kim, Y. 2011.  Three metabolites from an entomopathogenic bacterium, Xenorhabdus nematophila, inhibit larval development of Spodoptera exigua (Lepidoptera: Noctuidae) by inhibiting a digestive enzyme, phospholipase A (2). Insect Science 18: 282-288.
• Negrisoli, A.S., Garcia, M.S., Negrisoli, C.R.C.B., Bernardi, D. and da Silva, A. 2010.  Efficacy of entomopathogenic nematodes (Nematoda: Rhabditida) and insecticide mixtures to control Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) in corn crops. Crop Protection 29: 677-683.

Cutworms: A key pest of turfgrass foliage How to identify cutworms?

• Adult cutworm moths are yellowish brown or dark gray in color with several black dots on the wings. Full grown cutworm caterpillars are reddish or blackish brown color with greasy look (see below photo of a full grown caterpillar, which was found on turfgrass in my yard) and as shown in the picture, they curled into a C-shaped ball when disturbed (see photo below).

[caption id="attachment_79" align="alignleft" width="300" caption="C-shaped cutworm larva"][/caption]