Stinkbugs

June 20, 2012 in Uncategorized

The three main stinkbug pests in Delaware that cause damage to vegetables, fruits, and field crops are the recently introduced brown marmorated stink bug, native brown, and native green stinkbugs.  Read about stinkbugs in corn by clicking here:  http://agdev.anr.udel.edu/weeklycropupdate/?p=4332 The three species are pictured below (photos by P. Sylvester).

Brown Marmorated Stink Bug Adult.  Note the white bands on the antennae and the alternating white and black bands on the edges of the abdomen.

Brown Stinkbug.  While similar in appearance to the brown marmorated stink bug, the brown stinkbug does not have white bands on the antennae.  Another distinguishing feature is the light colored, yellowish underside of the native brown stinkbug versus the gray underside of the brown marmorated stink bug.
Green Stinkbug. 

Stinkbug Eggs.

Phillip Sylvester Extension Agriculture Agent, UD, Kent County.

Stinkbug Damage in Tomatoes

July 28, 2011 in Uncategorized

Samples of tomatoes and pole beans have come in to the extension office showing the typical symptoms of stink bug injury.  While the brown marmorated stink bug (BMSB) has had a lot of attention lately, green and brown stink bugs will cause damage as well.  All three species can be found in Delaware and will attack a wide variety of vegetables and grain crops.  Below is an article written a year ago (August 6th, 2010) by Jerry Brust, IPM Vegetable Specialist, University of Maryland, found the in the WCU talking about stinkbug damage in tomatoes:

 

Stinkbug Damage Common in Tomatoes This Year

Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu

This has been one of the worse years for stink bug damage in tomatoes that I have seen in a while. Just about every field I walk into has at least some damage while others have severe damage (>35% tomatoes not marketable). Cloudy spot of tomato fruit is caused by the feeding of various species of stink bug (SB). On green fruit the damage appears as whitish areas with indistinct borders (Fig. 1). Individual spots may be 1/1612 inch in diameter; or, the spots may merge and encompass a large area of the fruit surface. On ripe fruit the spots are golden yellow (Fig. 1). Peeling back the skin shows these areas as white shiny, spongy masses of tissue (Fig.1). This damage is most common from late July or early August until the end of the season, concurring with the activity and feeding of stink bugs. SBs are often difficult to see and usually go unnoticed as they spend much of the day on the ground beneath tomato plants, which results in monitoring problems. Only a few are necessary to cause the appearance of cloudy spot on many tomato fruit. Brown marmorated stink bugs (Fig. 2) as well as leaf-footed (Fig. 3) and tarnished plant bugs also have been observed in larger than usual numbers in tomato fields. The brown marmorated SB may be responsible for some of the more severe feeding damage observed in some tomato fields. The leaf-footed and tarnished plant bugs usually do not do as much damage to fruit as the larger stink bugs. Feeding damage by the immatures of any of the stink bugs often appears as yellow “star-bursts” on red fruit (Fig. 4), which causes a very small shallow white spongy area under the star-burst (Fig. 5).
Stink bugs and tarnished plant bugs usually move into the edges of tomato fields and seldom are found in the interior of the fields, suggesting that spraying the edges of fields could be used as a control tactic. Stink bugs and especially the leaf-footed and tarnished plant bugs, tend to move into tomato fields when preferred hosts that are adjacent to the fields are disturbed or dry out.
This is an extremely difficult pest to monitor and control. There are no good methods of monitoring these pests. Traps do not work well except for just a few species of stink bug, visually scouting for them has proven to be unreliable and too time consuming. Usually SB damage is only a nuisance, but this year it has resulted in large losses in some fields. Growers who have had damage before from stinkbugs may want to examine the edges of their fields carefully starting in mid-June for tomatoes with cloudy spot. If it is a dry year as this year has been, it would probably be best to start in early June checking for damage. There are some acceptable chemical choices for stink bug control. Pyrethroids (Warrior II, Baythroid XL, Mustang MAX), Venom, Leverage, Voliam Xpress, or Tombstone can be used to reduce damage. It should be understood that none of the chemicals will give complete control, but will reduce damage significantly compared with no chemical usage.


Figure 1. Severe stink bug feeding on green and red fruit. Outer skin peeled back showing spongy white area.

Figure 2. Brown Marmorated stink bug

Figure 3. Leaf-footed bug adult

Figure 4. Star-burst pattern of immature stinkbug feeding

Figure 5. Spongy white area under star-burst feeding stink bug feeding.

Stink Bugs and Corn

June 28, 2009 in Uncategorized

Stink bugs have always been a problem in some vegetable and fruit crops like tomatoes and peaches in certain seasons. However, over the last few years, we have seen considerable damage on field crops. Soybeans and corn have been attacked during seed development stages. The following is information on stink bug in corn.

During the last 2 seasons, we have seen what we feel is stinkbug damage to developing corn ears; however, we are still not sure of the extent of this problem in our area. We are currently seeing a few whorl stage no-till fields planted into burned down small grain covers exhibiting typical stinkbug damage – that is stunted and distorted plants. Reports from states to our south are indicating that stinkbug populations are higher in corn again this season. Information from the University of Georgia from 2008, where they have experienced problems, indicates that:

(a) Corn is most susceptible to stink bug injury during ear formation before tasseling.

(b) Bugs will feed through the sheath, causing a dead spot on the ear. As the ear expands it becomes distorted and curves, usually outward.

(c) Feeding during silking and pollen shed also will kill kernels on the ear. Once the ear has elongated, stink bug feeding during the blister and milk stages blasts individual kernels usually causing them to abort.

(d) Although we have not developed thresholds for our area, the following thresholds are used in the South: 25% infested plants (1 bug per 4 plants) as a threshold during ear elongation to pollen shed and 50% infested plants (1 bug per 2 plants) during the later part of pollen shed and blister/milk stage.

(e) Initially stink bugs tend to be more prevalent on the field edge, so only a perimeter spray may be needed.”

Stink bug feeding onf corn ear. Photo by Gordon Johnson, UD.

Information from Joanne Whalen, Extension IPM Specialist, UD.

Stink Bugs in Crops

March 31, 2009 in Uncategorized

The following are some slides about stink bug, an insect pest that we are seeing more of in crops in Delaware.

All adult stink bugs are shield-shaped. Green stink bugs are bright green and measure 14.0 to 19.0 mm long. The major body regions of the green stink bug are bordered by a narrow, orange-yellow line. When first laid, the barrel-shaped eggs of the green stink bug are yellow to green, later turning pink to gray. Eggs of the green stink bug measure 1.4 x 1.2 mm. Green stink bug nymphs are predominantly black when small, but as they mature, they become green with orange and black markings.

Brown stink bugs are dull brownish-yellow in color and 12.0 to 15.0 mm long. The white, kettle-shaped eggs of the brown stink bug are slightly smaller than those of the green stink bug. Nymphs of the brown species are light green.

The predatory Spined Soldier Bug, Podisus maculiventris, pictured on the right above, is a beneficial insect that feeds on insect pests. It is common in field crops, gardens, and in weedy areas where it feeds on caterpillars and other slow-moving arthropods. The spined soldier bug is about 1 cm long, full-grown. This beneficial insect can easily be mistaken for the brown stink bug pictured on the left above.

Stink bugs feed on over 52 plants, including native and ornamental trees, shrubs, vines, weeds, and many cultivated crops. The preferred hosts are nearly all wild plants. Stink bugs build up on these hosts and move to soybeans and corn later in the season as their preferred foods mature. Stink bugs inflict mechanical injury to the seed as well as transmit fungal disease organisms. The degree of damage caused by this pest depends to some extent on the developmental stage of the seed when it is pierced by the stink bug’s needlelike mouthparts. The younger the seed when damaged, the greater the yield reduction. Although late season infestations may not affect yield, bean oil content and germination will be reduced. In corn, stink bug damage can lead to deformed ears.

Stink bugs can damage many vegetable crops and will cause fruit damage such as cloudy spot on tomatoes and pod and seed damage in crops such as snap beans and lima beans.

Slides by Joanne Whalen, Extension IPM Specialist, UD. Some information from a fact sheet on stink bugs from North Carolina State University.

Stink bug Damage on Tomato

August 6, 2008 in Uncategorized

For the second year in a row, stink bug damage has been heavy in tomato fields and market gardens with tomatoes. The following are some pictures and some information.

Stink bugs have a distinctive shield shape and produce an odor when handled. There are several species of stink bugs that feed on tomato fruit, but the brown stink bug is the most serious. Stink bugs feed with piercing-sucking mouthparts which cause whitish-yellow corky spots underneath the skin of the fruit. This damage is serious for fresh market tomatoes because they render the fruit unmarketable.

Adult stink bugs migrate from weedy areas, windbreaks, roadsides, ditchbanks, and other non-crop areas into tomato fields and are more severe in dry periods when other plants are not as desirable to feed on. On green fruit, stink bug damage appears as a pin prick, surrounded by a light discolored area. This may turn yellow or remain green on ripe fruit and the tissue below these spots is corky.

Discoloration of fruit caused by stink bug feeding.

Stinkbug on Corn Ear

July 26, 2008 in Uncategorized

Stinkbugs can do damage to corn if in high enough numbers. The following is a picture I took in one of my research plots of a stinkbug feeding on a corn ear.


“Corn is most sensitive to stink bug injury during ear elongation before pollen shed. The treatment threshold at this stage is 1 bug per 4 plants (25% infested plants). Once pollination occurs, feeding though the husk causes damage to individual kernels. Kernels are susceptible to damage up until the milk stage (R3) and possibly early dough stage (R4). The threshold at this time is 1 bug per 2 plants (50% infested plants).” (picture by Gordon Johnson, UD; information on stinkbug damage is from the University of Georgia).

Gordon Johnson, Extension Agriculture Agent, UD, Kent County

Watch for Stink Bugs

July 14, 2008 in Uncategorized

Stink bugs are starting to increase in field and vegetable crops. Scout for these pests as they can cause significant yield reductions if in high enough numbers. The following is information from Joanne Whalen, UD IPM extension specialist.

As full season beans start to set pods in the next week to 10 days, you will also need to consider stink bugs. We have started to see an increase in both brown and green stink bug populations. Economic damage is most likely to occur during the pod development and pod fill stages. You will need to sample for both adults and nymphs when making a treatment decision. Available thresholds are based on beans that are in the pod development and fill stages. We are currently following the same guidelines that are being used in Virginia. Thresholds are also based on numbers of large nymphs and adults, as those are the stages most capable of damaging pods. As a general guideline, current thresholds are set at 1 large nymph/adult (either brown or green stink bug) per row foot if using a beat sheet, or, 2.5 per 15 sweeps in narrow-row beans, or 3.5 per 15 sweeps in wide-row beans.

In corn, as far as stinkbugs, we have no thresholds for our area; however, the following is information from Georgia: “Corn is most sensitive to stink bug injury during ear elongation before pollen shed. The treatment threshold at this stage is 1 bug per 4 plants (25% infested plants). Once pollination occurs, feeding though the husk causes damage to individual kernels. Kernels are susceptible to damage up until the milk stage (R3) and possibly early dough stage (R4). The threshold at this time is 1 bug per 2 plants (50% infested plants).”

In lima beans we are staring to see an increase in stinkbug and plant bug populations. As soon as pin pods are present, be sure to watch carefully for plant bug and stinkbug adults and nymphs. As a general guideline, treatment should be considered if you find 15 adults and/or nymphs per 50 sweeps. Bifenthrin (Brigade and a number of generics), Mustang MAX, Proaxis and lamda-cyhalothrin (Warrior and a number of generics) are labeled for both insects. The higher labeled rates will be needed if stinkbugs are the predominant insect present.

Green stinkbug nymph. Photo by Herb Pilcher, USDA Agricultural Research Service, Bugwood.org

Brown stinkbug adult. Photo by Russ Ottens, University of Georgia, Bugwood.org

Information from Joanne Whalen, Extension IPM Specialist, UD.

Stink Bug on the Rise in Soybeans.

August 26, 2007 in Uncategorized

Stink bugs are on the rise in soybeans. They are commonly a problem in vegetable crops such as lima beans and tomatoes. However in recent years we have seen build ups in soybeans.

From Joanne Whalen, UD IPM Extension Specialist in the Weekly Crop Update:

We have started to see an increase in populations of both green and brown stinkbugs. You will need to continue to scout for stinkbugs in fields that are in the pod development and pod fill stages. Economic damage is most likely to occur during these stages. You will need to sample for both adults and nymphs when making a treatment decision. Available thresholds are based on beans that are in the pod development and fill stages. We are currently following the same guidelines that are being used in Virginia. Thresholds are based on numbers of large nymphs and adults, as those are the stages most capable of damaging pods. As a general guideline, current thresholds are set at 1 large nymph/adult (either brown or green stink bug) per row foot if using a beat sheet, or, 2.5 per 15 sweeps in narrow-row beans, or 3.5 per 15 sweeps in wide-row beans. Since we have not done any research on stinkbug control, here is what Ames Herbert from VA indicated in his last newsletter: “Our research and others shows that brown stink bugs can be more difficult to kill with pyrethroids. If faced with a bad brown stink bug problem in soybeans, Orthene 97 at 8 oz/acre offers the best solution. For a lesser problem, a medium to high pyrethroid rate will do a lot.”

More on stink bugs from a fact sheet from the University of Missouri Extension modified for Delaware conditions:

In Delaware, the green stink bug, Acrosternum hilare (Say), and brown stink bugs, Euschistus spp., commonly infest soybean fields. Throughout North America, the green stink bug is tied for second among all insect species attacking soybean pods and seeds. Stink bugs are typically more of a problem in the southern states than in northern states. In Delware, we are seeing increases in stink bug feeding in soybeans in the last few years.

Stink bug at a glance
>Stink bugs produce a foul odor in self-defense.
>Both brown and green stink bugs attack both soybean pods and seeds.
>Stink bugs have piercing-sucking mouthparts that act like hypodermic needles to remove the plant’s fluids.
>Stink bugs affect the quality of soybeans by damaging seeds, yield by piercing seeds and causing seed abortion or reduced seed size, and in severe cases can cause pod drop (very high numbers piercing pods).

Description and life cycle

Stink bugs overwinter as adults underneath leaf litter, tree bark, and other materials in areas not used for crops. When spring time temperatures begin to increase, stink bugs become active and begin feeding on both cultivated and wild host plants. Adult green stink bugs are bright green with black bands on their antennae. They differ from southern green stink bugs, Nezara viridula (L.), by having a pointed (not rounded) spine between their hind legs. Adult brown stink bugs are brown with yellow to light-green undersides. They should not be confused with the spined soldier bug, Podisus maculiventris (Say), a predaceous stink bug species that also is brown and has a cream-colored underside. Spined soldier bugs differ from brown stink bugs by having more pronounced spines on their pronotum (shoulders), a black spot on their abdomen, and reddish legs.

Once overwintering adult stink bugs rebuild their energy reserves, they mate, and females begin laying their eggs in early summer. Females lay tight clusters of 10 to 30 barrel-shaped eggs on soybean plants. Depending on weather conditions, the nymphs will hatch within one to three weeks. The first-instar nymphs (the green stink bug is reddish brown; the brown stink bug is yellow to tan) do not feed and remain clustered on their egg masses. The green stink bug nymphs (second- and third-instars) are pale to dull green with black and white strips. Later instar nymphs are green with yellow and black strips or a pale, yellow-green color with black markings. All brown stink bug nymphs are yellow to tan with brown spots down the middle of their abdomen. Depending on the species and weather conditions, it takes between 23 days and two months to progress from the egg to adult stage. Depending on the species, stink bugs annually will have one to three generations in Delaware.

Damage

Both the nymphal and adult stages attack primarily the seeds and pods of soybean plants. They also will feed on soybean plant stems, foliage, and blooms. Usually the location of feeding punctures can be identified by the presence of small brown or black spots. Direct feeding damage can lead to a reduction in seed quality and quantity. Young seeds can be deformed, undersized or even aborted, whereas older seeds will be discolored and shriveled. The germination rate also will be reduced for beans produced as a seed source. Indirectly, feeding damage by stink bugs can delay plant maturity and cause the abnormal production of leaflets and pods. This condition is referred to as the “green bean effect.” For example, southern green stink bugs cause the most damage from the time soybean seeds begin to develop until they begin to fill.

Extracted and modified from:
Soybean Pest Management: Stink Bugs
Michael L. Boyd and Wayne C. BaileyState Extension Entomology Specialists

University of Missouri

Stinkbugs in Soybeans

August 12, 2007 in Uncategorized

Green Stink Bug Feeding on Soybean Pod
Photo by Kevin D. Arvin, Bugwood.org
You should start looking for stinkbugs in fields that are in the pod development and pod fill stages. Economic damage is most likely to occur during these stages. Populations of stinkbugs have been lower this year compared to last but we have just seen an increase in green stinkbug populations in Sussex County and southern Kent County. You will need to sample for both adults and nymphs when making a treatment decision. Available thresholds are based on beans that are in the pod development and fill stages. We are currently following the same guidelines that are being used in Virginia. Thresholds are also based on numbers of large nymphs and adults, as those are the stages most capable of damaging pods. As a general guideline, current thresholds are set at 1 large nymph/adult (either brown or green stink bug) per row foot if using a beat sheet, or 2.5 per 15 sweeps in narrow-row beans, or 3.5 per 15 sweeps in wide-row beans.

From Joanne Whalen, Extension IPM Specialist, University of Delaware

Know Your “True Bugs” That Are Pests of Crops

August 7, 2007 in Uncategorized

The insect order Hemiptera is commonly referred to as the “True Bugs”. There are some very important agricultural pests in this group and we are seeing more of them as the summer advances. This includes brown and green stinkbugs in soybeans, tomatoes, and other fruit and vegetable crops; harlequin bugs in cole crops; Lygus (tarnished plant) bugs in lima beans; squash bug on pumpkins, winter squash, and summer squash; and aphids of many types in many crops. These all are piercing-sucking insects and do damage to plants by inserting their needle-like stilet into the plant tissue and sucking up the plant sap. They have an incomplete metamorphosis, that is they hatch from eggs into a nymph which completes several molts before becoming the adult form.

Squash Bug
Photo by Whitney Cranshaw, Colorado State University, Bugwood.org

Soybean Aphid
Photo by David W. Ragsdale, University of Minnesota, Bugwood.org

Green Peach Aphid

Photo by Whitney Cranshaw, Colorado State University, Bugwood.org

Melon Aphid
Photo From Mississippi State University Archive, Mississippi State University, Bugwood.org

Greenbug on Sorghum
Photo by Alton N. Sparks, Jr., University of Georgia, Bugwood.org

Lygus or Tarnished Plant Bug
Photo by Scott Bauer, USDA Agricultural Research Service, Bugwood.org

Harlequin Bug
Photo from Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org

Green Stinkbug (different species from southern green stinkbug) Nymph
Photo by Herb Pilcher, USDA Agricultural Research Service, Bugwood.org

Southern Green Stinkbug
Photo by Herb Pilcher, USDA Agricultural Research Service, Bugwood.org

Brown Stinkbug
Photo by Russ Ottens, University of Georgia, Bugwood.org