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Extension Entomology

Category: Greenhouse

New Extension Publication

–by Dr. Raymond Cloyd

We have a new extension publication available entitled, Scale Insect Pests

 

This new extension publication provides information on the biology, scale types, plant damage, and offers strategies for managing specific types of scales. There are color images of the scale insect pests found in Kansas and surrounding states. The extension publication is available from the following website:

https://www.bookstore.ksre.ksu.edu/pubs/MF3457.pdf

 

Japanese Beetles

— by Dr. Raymond Cloyd

Japanese beetle, Popilla japonica, adults are present in most regions of Kansas feeding on different plant species, including: roses, Rosa spp.; littleleaf linden, Tilia cordata; and Virginia creeper, Parthenocissus quinquefolia, among many other plant species. The ways to manage populations of the adult stage of Japanese beetle are limited, and have been for many years, with the use of insecticides still being the primary strategy. Japanese beetle adults are one of the most destructive insect pests of horticultural plants in landscapes and gardens. Furthermore, the larva or grub is a turfgrass insect pest in home lawns, commercial settings, and golf courses.

 

Japanese beetle adults are 9/16 of an inch long, metallic green with coppery-brown wing covers, and about 14 tufts of white hair are present along the edge of the abdomen (Figure 1).

Fig 1. Japanese Beetle Adults Feeding On Leaf (Auth–Raymond Cloyd, KSU)

Adult Japanese beetles emerge from the soil and live up to 45 days feeding on plants over a four-to-six-week period. Adults feed on many horticultural plants including: trees, shrubs, vines, herbaceous annual and perennials, vegetables, fruits, and of course—roses. Plant placement in the landscape and the volatiles emitted by plants are factors that affect adult acceptance. In addition, Japanese beetle adults produce aggregation pheromones that attract males and females to the same feeding location. Adults can fly up to five miles to locate a host plant; however, they tend to only fly short distances to feed and for females to lay eggs.

Japanese beetle adults feed through the upper leaf surface (epidermis) and leaf center (mesophyll), leaving the lower epidermis intact. Adults avoid feeding on tissue between leaf veins, resulting in leaves appearing lace-like or skeletonized (Figure 2).

Fig 2 Japanese Beetle Adult Feeding Damage On Leaf (Auth–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 to flower. Japanese beetle adults start feeding at the top of plants, migrating downward after depleting food sources. Japanese beetle adults will also feed on flowers (Figure 3),

Fig 3. Japanese Beetle Adults Feeding On Rose Flower (Auth–Raymond Cloyd, KSU)

chewing holes in flower buds, which prevents flowers from opening or causes petals to fall prematurely.

Managing Japanese beetle adult populations involves implementing a variety of plant protection strategies, including: cultural, physical, and applying insecticides. Cultural control is affiliated with maintaining healthy plants through proper irrigation, fertility, mulching, and pruning, which are important in minimizing ‘stress’, and may possibly decrease susceptibility. Moreover, removing weeds that are attractive to Japanese beetle adults such as smartweed (Polygonum spp.) may help to reduce infestations. Physical control involves hand-picking or collecting Japanese beetle adults from plants 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, for at least three weeks, particularly after adults emerge, may substantially reduce plant damage. A study reported that collecting Japanese beetle adults daily at 7:00 pm had the greatest impact on populations and reduced subsequent damage.

 

In general, the use of Japanese beetle traps (Figure 4) in a landscape or garden is not recommended since the floral lure and synthetically-derived sex pheromone may attract more adults into an area than would ‘normally’ occur. Japanese beetle adults may also feed on plants before reaching the traps, which increases potential damage.

 

Spray applications of contact insecticides will kill Japanese beetle adults. However, repeat applications are required; especially when populations are excessive. Several pyrethroid-based insecticides; such as those containing permethrin (Sevin®), bifenthrin or cyfluthrin as the active ingredient, will suppress Japanese beetle adult populations. However, most of these insecticides will also directly harm many natural enemies (parasitoids and predators) and continual use will result in secondary pest outbreaks of other pests including the twospotted spider mite, Tetranychus urticae. In addition, 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 against Japanese beetle adults because they have to feed on leaves and consume lethal concentrations of the active ingredient. If extensive populations are present, plant damage can still occur.

 

PHOTO NOT AVAILABLE

The battle against Japanese beetle adults requires diligence, patience, and persistence, to prevent adults from causing substantial damage to plants in landscapes and gardens.

 

 

Mosquitoes: How to Avoid Being “Bitten” by This “Sucking” Insect

–by Dr. Raymond Cloyd

The current wet weather and standing water has provided “perfect” conditions for mosquitoes (Figures 1 and 2). The three primary strategies that must be implemented to avoid mosquito problems and bites are: 1) source reduction, 2) personnel protection, and 3) insecticides.

Fig 1. Mosquito Sucking Blood (Author–Inverse

Fig 2. Mosquito Magnet Sign (Auth–Raymond Cloyd, KSU)

1) Source Reduction
It is important to routinely eliminate or reduce all mosquito breeding sites, which will effectively decrease mosquito populations, by removing stagnant or standing water from items or areas that may collect water. These include the following:
* Wheelbarrows
* Pet food or water dishes
* Saucers/dishes underneath flower pots
* Empty buckets
* Tires
* Toys
* Wading pools
* Birdbaths
* Ditches
* Equipment
* In addition, check gutters regularly to ensure they are draining properly and are not
collecting water

2) Personnel Protection
Protect yourself from mosquito bites by delaying or avoiding being outdoors during dawn or dusk when most mosquitoes are active. Use repellents that contain the following active ingredients: DEET (Figures 3 and 4) or picaridin (Figure 5). Generally, DEET provides up to 10 hours of protection whereas picaridin provides up to 8 hours of protection. A product with a higher percentage of active ingredient will result in longer residual activity or repellency. For children, do not use any more than 30% active ingredient. Furthermore, do not use any repellents on infants less than two months old. Clothing can be sprayed with DEET or permethrin (pyrethroid insecticide). However, be sure to wash clothing separately afterward. Before applying any repellent, always read the label carefully.

Fig 3. DEET Repellents (Auth–Raymond Cloyd, KSU)

Fig 4. DEET Repellent (Auth–Raymond Cloyd, KSU)

Fig 5. Repellent With Picaridin (Auth–Raymond Cloyd, KSU)

3) Insecticides

For stationary ponds, there are several products that may be used, such as; Mosquito Dunks and/or Mosquito Bits (Figure 6). Both contain the active ingredient, Bacillus thuringiensis subsp. israelensis, which is a bacterium ingested by mosquito larvae that results in death. The bacterium only kills mosquito larvae with no direct effects to fish or other vertebrates. Avoid making area-wide applications of contact insecticides because these are generally not effective, and may potentially kill many more beneficial insects and pollinators (e.g. bees) than mosquitoes.

Fig 6. Mosquito Dunks and Mosquito Bits (Auth–Raymond Cloyd, KSU)

What Does Not Work Against Mosquitoes 

The following items will not control mosquitoes:

* Mosquito repellent plants (citronella plants)

* Bug zappers

* Electronic emitters

* Light traps/carbon dioxide traps.

If anyone has questions or comments regarding mosquito control please contact your county extension office or Department of Entomology at Kansas State University (Manhattan, KS).

Termites

— by Dr. Jeff Whitworth and Dr. Holly Davis

The last few days of warm, sunny conditions after the preceding few days of cooler, wet weather have apparently initiated considerable termite swarming activity.

Again, make sure to positively identify the insects swarming, as ants are also actively swarming.  There is a huge difference in damage potential between termites and ants, even carpenter ants.  So, please refer to these KSU extension publications to properly identify and manage ants and termites:

 

Termites, MF722: https://www.bookstore.ksre.ksu.edu/pubs/MF722.pdf

Ants, MF2887: https://www.bookstore.ksre.ksu.edu/pubs/MF2887.pdf

Common Asparagus Beetle

–by Dr. Raymond Cloyd

If you are growing asparagus then it is that time of year to be aware of the only insect pest of asparagus; the common asparagus beetle, Crioceris asparagi. Adult beetles are 1/4 inch long. The body is metallic blue to black with red margins and six cream-colored markings (Figure 1).

Figure1. Common Asparagus Beetle Adult (Author–Raymond Cloyd, KSU)

Adults emerge from the soil in early spring and fly to new asparagus shoots where they mate and feed. Females lay up to 30 eggs on the end of spear tips as they emerge from the soil (Figure 2)

Figure2. Common Asparagus Beetle Eggs on Spear Tip of Asparagus (Author–Raymond Cloyd, KSU)

Larvae hatch from eggs after about a week, migrate onto the ferns, and commence feeding. The larvae look like a small slug. They are wrinkled, 1/3 inch in length, and olive-green to gray with black heads and legs (Figure 3).

 

Figure3. Common Asparagus Beetle Larvae Feeding on Asparagus (Author–Raymond Cloyd, KSU)

Larvae feed for approximately two-weeks and then drop to the ground, burrow into the soil, and form a yellow pupa. After several weeks, adults emerge and start feeding. Common asparagus beetles overwinter underneath plant debris, loose bark, or hollow stems of old asparagus plants. The life cycle can be completed in eight-weeks. There are two generations in Kansas.

The adults and larvae feed on asparagus spears and can defoliate ferns if populations are extensive. Larvae consume leaves and tender buds near the tips, which leaves scars that eventually turn brown. Damage caused by larvae interferes with the plant’s ability to photosynthesize (manufacture food); thus depleting food reserves for next year’s crop.

The plant protection strategies that can be implemented to reduce problems with common asparagus beetle populations include: applying insecticides; hand-picking eggs, adults, and larvae and placing into a container with soapy water; and/or removing any plant debris after the growing season to eliminate overwintering sites for adults. Insecticides should be applied as soon as common asparagus beetles are present, and again in late summer through early fall to kill adults before they overwinter. Thorough coverage of all plant parts is important in suppressing populations.

 

 

 

Dormant Oils

–by Dr. Raymond Cloyd

Dormant oils are applied during winter in order to deal with insect and mite pests that survive the winter in overwintering life-stages, such as eggs or mature females. Instead of waiting until spring to initiate “control” measures, the application of dormant oils may be helpful in reducing costs associated with pesticide inputs (in this case, insecticides and miticides) later in the season (spring through fall). The advantages of applying dormant oils include: 1) a wide range of activity against most species of mites and scales—even the eggs; 2) minimal potential for resistance developing in insect and/or mite pest populations; 3) less direct and indirect harmful effects to beneficial insects and predatory mites compared to pesticides with long-residual activity; and 4) relatively low toxicity to humans and other mammals. The disadvantages of dormant oils include; potential phytotoxicity during the growing season and minimal residual activity or persistence.

Dormant oils are typically derived from paraffinic crude oil, and are the heaviest of the petroleum-based oil sprays with a low unsulfonated residue (Figure 1).

figure-1-dormant-oil-product

Figure 1: Dormant Oil Product

The unsulfonated residue is an assessment of the phytotoxic compounds remaining after distillation and refining. An unsulfonated residue >92% indicates a highly refined product with less potential for phytotoxicity. Dormant oils generally have a unsulfonated residue value <92%.

Dormant oil applications are primarily directed at killing overwintering pests including certain mites and scales (Figure 2),

figure-2-dormant-oil-product-label-information

Figure 2: Dormant Oil Product Label Information.

before they become active in the spring and are capable of causing plant injury. Applications are made during winter so as to minimize phytotoxicity to ornamental plants. A 2% to 4% application rate is generally recommended in late fall to early spring. Dormant oils have contact activity and either suffocate; by blocking the breathing pores (spiracles), or directly penetrate and disrupt cell membranes of exposed insect and mite pests. However, dormant oils have minimal residual activity once residues dissipate, so thorough coverage of all plant parts is essential.

Since dormant oils are applied to all plant parts, the overwintering stage of the insect or mite pest must be located on the plant. However, not all insect and mite pests overwinter on plants. For example, dormant oil applications are not effective against the twospotted spider mite (Tetranychus urticae) because the mite overwinters as a female in plant debris, mulch, or other non-plant protected places. In contrast, the spruce spider mite (Oligonychus ununguis) overwinters as an egg on plants, primarily evergreens such as arborvitae, hemlock, juniper, and pine; so the spruce spider mite is susceptible to dormant oil sprays.

Dormant oils are effective in killing the overwintering stages of scales, especially first and second instars or nymphs (=crawlers). For example, euonymus scale (Unaspis euonymi) overwinters as second instar nymphs or mature females; both life stages are susceptible to dormant oil applications. However, certain scales that overwinter as eggs such as oystershell scale (Lepidosaphes ulmi) and pine needle scale (Chionaspis pinifoliae) are more tolerant of dormant oil applications because the eggs are generally stacked or piled on top of each other. Subsequently, dormant oils may not penetrate and contact the bottom layer. As a result, additional insecticide applications are typically required after egg hatch.

An issue when using dormant oils is the potential for plant injury or phytotoxicity. Some plants, such as arborvitae, beech, redbud, and certain maples (Japanese, red, sugar, and amur), may be harmed by dormant oil sprays. Furthermore, the needles of Colorado blue spruce (Picea pungens) may be discolored or change from blue to green as a result of a dormant oil application. Phytotoxicity may be a problem when >4% application rates are used and/or when applications are performed in early fall before dormancy or in late spring at bud-break. Problems associated with phytotoxicity are less likely to occur when applications are made in early November through February, which is when most plants are completely dormant. In order to avoid phytotoxicity, always ensure the spray solution is continually agitated. Also, never apply dormant oils when temperatures are ≤32ºF. Dormant oils should be applied to deciduous plants when the ambient air temperature will stay above freezing for at least 24 hours. Evergreens, in general, are more susceptible to damage than deciduous plants, so it is best to apply dormant oils when temperatures remain above 40ºF over a 24-hour period although there is no quantitative evidence suggesting that applications made at <40°F will damage dormant fruit trees. In addition, general recommendations are that dormant oils should never be applied to plants that are stressed since stressed plants are more susceptible to phytotoxicity. For example, lack of moisture, extreme temperatures, and sudden drastic changes in the ambient air temperatures after spraying, prolonged windy conditions, and disease or insect infestations may predispose plants to phytotoxicity. However, there is no direct evidence indicating that dormant oils are harmful to stressed trees.

There is a general misconception that insect and mite pest populations are unable to develop resistance to dormant oils. However, this is not true. For instance, a Christmas tree plantation of Scots pine (Pinus sylvestris) trees was sprayed with dormant oils for more than 10 years in succession to “control” pine needle scale. Eventually, the scale population became more and more difficult to “control.” Why? Well, what was discovered was that the scale covers actually increased in thickness; making it difficult for the dormant oil to penetrate the outer covering and kill the eggs.

Preventative dormant oil applications may avoid dealing with abundant insect and/or mite pest populations during the season. Therefore, inputs from insecticide and/or miticide applications may be reduced, thus preserving the natural enemies of mites and scales, including; predators and parasitoids that may naturally regulate populations of these pests.

 

Kansas Greenhouse Growers Association 2016 Biological Control Workshop

–by Dr. Raymond Cloyd

 

Kansas Greenhouse Growers Association 2016 Biological Control Workshop

OCTOBER 18, 2016

POTTHORF HALL, MANHATTAN, KS

 

SCHEDULE

8:00 to 9:00 AM         Registration

9:00 to 10:00 AM       Fundamentals of biological control (Dr. Raymond Cloyd)

10:00 to 10:45 AM     How to succeed using biological control (Chris Fifo)

figure7-1

 

10:45 to 11:30 PM      The challenges associated with rearing natural enemies (Brian Spencer)

11:30 to 12:15 PM      Panel Discussion: Why we use biological control (Tim Sullivan, Karen Pendleton, and Eric or Evan Nelson)

12:15 to 1:00 PM        Lunch

1:00 to 3:00 PM          Demonstrations and samples of beneficial insects, mites, and nematodes (Dr. Raymond Cloyd, Brian Spencer, and Chris Fifo)

3:00 to 3:30 PM          Conclusion and Evaluation

figure7-5

figure7-8

figure7-11

 

Kansas Greenhouse Growers Association

 Biological Control Workshop

October 18, 2016

 

POTTORF Hall

1710 Avery Drive

Manhattan, KS 66503

CICO Park

 

REGISTRATION FORM

 

Name: ­________________________________________________________________________________

 

Business Affiliation: ______________________________________________________________________

 

Address: ­______________________________________________________________________________

 

City/Count/State/Zip: _____________________________________________________________________

 

Phone: ( _____ ) _______________ Fax: ( _____ ) _______________ E-Mail: _______________________

 

Additional Attendees (needed for name badges):

 

  1. ________________________________________ 2. ________________________________________

 

  1. ________________________________________ 4. ________________________________________

 

Total Number Attending: _____________

 

 

 

One Day Event:

 

Individual                                                                              ___________ @ $  50 = __________

Vendor                                                                                   ___________ @ $100 = __________

Student                                                                                  ___________ @ $  15 = __________

 

Please send a check made out to: “The Kansas Greenhouse Growers Association” OR pay with a check at the registration desk at the workshop.

 

 

Return to:            Dr. Raymond Cloyd

Department of Entomology

Kansas State University

123 Waters Hall

Manhattan, KS 66506-4004

Rose Sawflies

–by Raymond Cloyd

There are at least two species of sawflies that attack roses during this time of year; the rose slug (Endelomyia aethiops) and bristly rose slug (Cladius difformis). Rose slugs are the immature (larval) stage of sawflies, which are black to yellow-colored wasps.

Rose sawfly females make pockets or slits along the edges of rose leaves using their saw-like ovipositor (egg-laying devise), and insert individual eggs. Eggs hatch into larvae that look-like a slug. Larvae are 1.2 cm in length when fully grown and yellow-green in color, with an orange head (Figure 1). The larvae eventually fall on the soil surface to

Figure1RoseSawflyLarvaeFeedingOnLeafUnderside

pupate. Rose slugs overwinter as pupae in earthen cells created by the larvae. There is usually one generation per year in Kansas. Bristly rose slug larvae are pale-green in color and 1.5 to nearly 2.0 cm long. The body is covered with numerous bristle-like hairs (Figure 2). There is generally one generation per year in Kansas.

Figure2BristlyRoseSlugLarvaeFeedingOnLeafUnderside

 

Rose slug larvae feed on the underside of the leaf resulting in the leaves having a skeletonized appearance (Figure 3), eventually they create notches or holes on the leaf margins. Bristly rose slug larvae feed on the leaf undersides and also cause leaves to appear skeletonized (Figure 4). However, the larvae may chew larger holes than the rose slug.

Figure3FeedingDamageCausedByRoseSawflyLarvae

Small infestations of either the rose sawfly or bristly rose slug can be removed by hand and subsequently placed into a container of soapy water. A forceful water spray will quickly dislodge sawfly larvae from rose plants; consequently, sawfly larvae are not able to crawl back onto rose plants. A number of contact insecticides (various active ingredients) may be effective in suppressing populations of both sawflies. However, the bacterium, Bacillus thuringiensis subsp. kurstaki (sold as Dipel or Thuricide) will have no activity on sawflies as this compound only works on caterpillars.

Figure4FeedingDamageCausedByBristlyRoseSlugLarvae

 

 

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