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Extension Entomology

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Praying Mantid Egg Cases

— by Raymond Cloyd

Praying mantid adults are 3 to 4 inches (76 to 102 mm) long, elongated, slow-moving generalist insect predators that wait for prey with their upraised front legs (Figure 1).

Fig 1. Praying Mantid with Front Legs Upraised (Auth–Raymond Cloyd, KSU)

They eat “anything” they can grab onto with their raptorial front legs including: flies, crickets, moths (Figure 2),

Fig 2. A Praying Mantid Eating a Moth (Auth–Raymond Cloyd, KSU)

butterflies, wasps, and caterpillars. In addition, praying mantids will feed on honey bees entering and leaving hives. Praying mantid females lay between 200 and 300 eggs that are covered by a hardened, Styrofoam-like egg case or ootheca produced by the female. The egg cases can be found on branches (Figure 3),

Fig 3. Praying Mantid Egg Case on Branch (Auth–Raymond Cloyd, KSU)

stems, walls, fences, sides of houses (Figure 4),

Fig 4. Praying Mantid Egg Case Attached To Side of House (Auth–Raymond Cloyd, KSU)

and eaves. Egg cases may be present from November through April. Nymphs hatch (eclose) from eggs in three to 10 weeks depending on temperature. Nymphs that emerge in spring resemble miniature adults (Figure 5).

 

Fig 5. Praying Mantid Nymphs That Have Emerged From Egg Case (Auth–Josh’s Frogs)

However, not all the nymphs will survive to become adults because they are susceptible to predation by vertebrates (birds, toads, and lizards) and predacious insects. Praying mantids overwinter as eggs.

 

 

Egg cases can vary in size and shape depending on species. The egg case of the Carolina mantid, Stagmomantis carolina, is tan to light-brown, about 1.0 inch (25 mm) long, rectangular or elongated, rounded at the top and bottom, and there is a distinct white to gray band that extends down the center of the egg case (Figure 6).

Fig 6. Egg Case of The Carolina Mantid (Auth–The Amazing Plant Project)

The egg case of the Chinese mantid, Tenodera aridifolia sinensis, is light-brown, approximately 1-1/2 inches (38 mm) long, half-domed shaped, with one end tapered (Figure 7).

Fig 7. Egg Case of Chinese Mantid on Branch (Auth–Raymond Cloyd, KSU)

Egg cases can be purchased from garden centers, nurseries, or mail order sources (Figure 8). Most egg cases for sale are associated with the Chinese mantid, which is not native to North America; however, the species has become naturalized in most regions. The purchase of praying mantid egg cases is not recommended because praying mantids will not effectively regulate most insect pest populations or will not kill enough insect pests to prevent damage. Nonetheless, having praying mantids in the garden provides an educational opportunity for people to observe nature in action!

Fig 8. Product Containing Egg Cases of The Chinese Mantid (Auth–Raymond Cloyd, KSU)

Well, how can I collect and preserve praying mantid egg cases? You can remove the egg case, bring them into the home, and place into a glass jar with a lid that has least 10 small air holes. The warm temperatures inside the home will cause the nymphs to hatch from eggs in four to six weeks. You can delay egg hatch by placing the egg cases into a refrigerator and remove one to two months before you want the eggs to hatch. This will ensure that nymphs are released when the weather is warm so there is no risk of exposure to cold temperatures. The nymphs that emerge will be very hungry. Therefore, immediately release them into the garden, as long as they will not be exposed to freezing temperatures. However, if the nymphs are not released promptly or provided with a food source, they will eat each other (cannibalism) leaving just one large nymph that will not eat for a month.

Japanese Beetles Are Back!

–by Dr. Raymond Cloyd

Japanese beetle adults are out in full-force in certain regions of Kansas feeding on different plant species, but especially roses (Rosa spp.). The means of dealing with the adult stage of Japanese beetle are limited, and have been for many years, with the use of insecticides still being the primary plant protection strategy. Japanese beetle, Popillia japonica is native to Japan and was first reported in the United States in 1916 in the state of New Jersey. Currently, Japanese beetles are established from Maine to Georgia and in nearly every state east of the Mississippi River and several mid-western states.

Figure 1. Japanese beetle adult (Author-Raymond Cloyd, KSU)

Japanese beetles are established in eastern and central portions of Kansas, and are slowly moving westward. Japanese beetle adults are one of the most destructive insect pests of horticultural plants in both landscapes and gardens. The larvae or grub is a major turfgrass insect pest in home lawns, commercial settings, and golf courses.

Japanese beetle adults are 9/16 of an inch in length and metallic green with coppery-brown wing covers (Figure 1). There are about 14 tufts of white hair present along the end of the abdomen (Figure 2). Adult Japanese beetles emerge from the soil and live from 30 to 45 days feeding on plants over a four-to-six-week period.

Figure 2. Japanese beetle adult. Note tufts of white hair on the end of the abdomen (Author-Raymond Cloyd, KSU)

Adults feed on many ornamental plants including: trees, shrubs, vines, herbaceous annual and perennials, and of course—roses. Plant placement in the landscape and volatiles emitted by plants are factors that can influence adult acceptance. Moreover, Japanese beetle adults produce aggregation pheromones that attract individuals (both males and females) to the same feeding location. Adults can fly up to five miles to locate a feeding site; however, they tend to fly only short distances to feed and lay eggs.

Japanese beetle adults feed through the upper leaf surface (epidermis) and leaf center (mesophyll), leaving the lower epidermis intact. Adults usually avoid feeding on tissue between leaf veins, resulting in leaves appearing lace-like or skeletonized (Figure 3).

Figure 3. Lace-like or skeletonized damage to leaf caused by Japanese beetle adult feeding (Author-Raymond Cloyd, KSU)

They are most active during warm days, feeding on plants exposed to full sun throughout the day, which is likely why roses are a susceptible host plant because roses require at least six hours of direct sunlight in order to flower. Japanese beetle adults start feeding at the top of plants, migrating downward after depleting food sources. Japanese beetle adults aggregate in masses on rose flowers (Figure 4). Although adult beetles feed mainly on flowers, they will also feed on leaves (Figure 5). Adults chew holes in flower buds;

Figure 4. Japanese beetle adults aggregating on rose flower (Author-Raymond Cloyd, KSU)

 

 

Figure 5. Japanese beetle adults feeding on linden (Tilia spp.) leaf (Author-Raymond Cloyd, KSU)

preventing flowers from opening or causing petals to fall prematurely. Furthermore, adults will consume entire rose petals, and feed on the pollen of fully-opened flowers.

Japanese beetle adult management involves implementing a variety of plant protection strategies, including: cultural, physical, and insecticidal. Cultural is associated with maintaining healthy roses through proper irrigation, fertility, mulching, and pruning, which are important in minimizing “stress, which may possibly decrease susceptibility. In addition, removing weeds such as smartweed (Polygonum spp.) that are attractive to Japanese beetle adults may alleviate infestations. Physical involves hand-picking or collecting Japanese beetle adults from roses before populations are extensive. The best time to hand-pick or collect adults is in the morning when ambient air temperatures are typically “cooler.” Adults can be easily collected by placing a wide-mouthed jar or bucket containing rubbing alcohol (70% isopropyl alcohol) or soapy water underneath each adult, and then touching them. Adults that are disturbed fold their legs perpendicular to the body, and fall into the liquid and are subsequently killed. This procedure, when conducted daily or every-other-day, particularly after adults emerge, may substantially reduce plant damage. The use of Japanese beetle traps (Figure 6)

Figure 6. Japanese beetle trap (Author-Raymond Cloyd, KSU)

 

is not recommended since the floral lure and synthetically-derived sex pheromone (Figure 7) may attract more adults into an area than would “normally” occur. Japanese beetle adults may also feed on roses before reaching the traps, which increases potential damage.

Figure 7. Floral lure (on left) and sex pheromone (on right) associated with Japanese beetle trap (Author-Raymond Cloyd, KSU) (PICTURE NOT SHOWN)

 

Spray applications of contact insecticides will kill Japanese beetle adults. However, repeat applications will be required; especially when populations are excessive. In addition, thorough coverage of all plant parts will increase effectiveness of the application. The insecticide carbaryl (Sevin®) and several pyrethroid-based insecticides including those containing bifenthrin or cyfluthrin as the active ingredient can be used to suppress Japanese beetle adult populations. However, most of these insecticides also directly harm many natural enemies (parasitoids and predators) so their continual use may lead to secondary pest outbreaks of other pests including the twospotted spider mite (Tetranychus urticae). Furthermore, these insecticides are directly harmful to honey bees and bumble bees. Therefore, applications should be conducted in the early morning or late evening when bees are less active. In general, systemic insecticides, are not effective because Japanese beetle adults have to feed on leaves and consume lethal concentrations of the active ingredient. If extensive populations are present, then damage to plants may still occur.

The battle against Japanese beetle adults requires patience, persistence, and diligence in order to prevent adults from causing substantial damage to roses and other susceptible plants.

 

European Pine Sawfly

–Dr. Raymond Cloyd

Yesterday (April 17, 2017) European pine sawfly, Neodiprion sertifer larvae were detected feeding on my “indicator pine” in Manhattan, KS (I was totally excited!). Young caterpillar-looking larvae are 1/4 inch in length and olive-green in color with a black head (Figures 1). Mature larvae are >1.0 inch long with green stripes. The larvae are gregarious or feed in groups on needles of a variety of pines, especially Scotch, red, and mugo pine. When disturbed, each individual larva will arch their head and abdomen (last segment of an insect body) back, forming a “C-shape” (Figure 2), which is a defensive posture to ward-off predators.

Figure 1. Young European Pine Sawfly Larvae

Eventually, larvae will strip the needles of mature foliage, leaving only the central core, which is white and then turns brown (Figure 3). In general, larvae complete feeding by the time needles emerge from the candelabra. Therefore, those really is only a minor threat of branch or tree death resulting from sawfly larval feeding. However, the loss of second- and third-year needles will be noticeable in landscape trees; thus ruining their aesthetic appearance. In late spring, larvae drop to the ground and pupate in brown, leathery cocoons located at the base of trees. Adults, which are wasp-like, emerge in fall and lay eggs in needles prior to the onset of winter. There is one generation per year in Kansas.

Figure 2. European Sawfly Larvae In A Defensive Posture (Arching Head And Abdomen Back)

Sawfly larvae look-like caterpillars; but, they are not caterpillars (Order: Lepidoptera). Sawflies are related to ants, bees, and wasps (Order: Hymenoptera). The primary way to distinguish a sawfly larva from a caterpillar is by the following: 1) sawfly larva have prolegs (fleshy abdominal legs) on every abdominal segment whereas caterpillars are missing prolegs on the abdomen and 2) caterpillar larva have hairs or crochets on their feet whereas sawfly larva do not have hairs or crochets on their feet.

Figure 3. Feeding Damage To Pine Caused By European Pine Sawfly Larvae

Sawfly larvae are not caterpillars, therefore, the bacterial insecticide, Bacillus thuringiensis subsp. kurstaki (sold as Dipel) will not directly kill sawfly larvae. Dealing with sawfly larvae involves hand-picking (you can wear gloves if you wish) or dislodging larvae from plants by means of a forceful water spray. If necessary, there are a number of insecticides that may be applied to suppress European pine sawfly populations including: acephate (Orthene), azadirachtin, carbaryl (Sevin), spinosad (Captain Jack’s DeadBug Brew and Conserve), and any pyrethroid insecticide (e.g., bifenthrin, cyfluthrin, and lambda-cyhalothrin). Be sure to read the insecticide label to make sure that sawflies are listed. For more information regarding European pine sawfly management contact your county or state extension specialist.

 

Wheat Pests

–by Dr. Jeff Whitworth, Dr. Holly Schwarting and JR Ewing

Worms (fall armyworms and armyworms) are still active in wheat and can be for another month, depending upon the weather.  If growing conditions are good, the wheat should be able to outgrow feeding caused by small worms.  Large worms have probably caused most of their feeding damage already, and hopefully, won’t be able to pupate, emerge as adults, lay eggs and have those eggs hatch again this fall.  Winter grain mites may cause some concern in the next month or so, especially under dry conditions. However, insecticide applications are rarely warranted or impact next year’s yield.  Again, good growing conditions will mitigate winter grain mite feeding damage.

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