Reports from Extension Entomologists in Tennessee and Arkansas indicate that fall armyworm (FAW) populations in soybean are building up earlier and in larger numbers than normal.  In Arkansas fields are being treated for a combination of FAWs and Corn earworm (CEW).  In Tennessee the populations do not appear to be as widespread but some fields were in need of treatment.  We can have this combination of insects in Kentucky soybeans. It is unusual, but it does occasionally happen.  Likely places to check are late planted beans and fields in which the canopy has never closed. Historically, when this problem has occurred it is usually found in the Purchase area and the southern tier of counties in the Pennyrile area. No problems have yet been reported in Kentucky. Nevertheless, producers, consultants and scouts should be scouting regularly for these pests. They are in Kentucky; that is not the question. The question remains as always; are populations large enough to warrant a control? See the following article on late season soybean pests for thresholds and controls.

As our soybean crop passes through the reproductive stages and into the pod filling stages the insect pest complex of likely importance begins to change. This change is due to the increasing importance of pod and bean damage, and reduced importance of foliar feeding.  For sure, severe foliar feeding can still reduce yield because these leaves, especially the upper 1/3 of the canopy, produces the nutrients that “fill” the beans. Nevertheless, we rarely see infestations of foliar feeding insects significant enough to reduce yields. The two foliar feeders that could present such a problem are green clover worm (GCW) and fall armyworm (FAW). Both of these insects are relatively easy to detect and to control if necessary. A treatable population is possible, but improbable.

Figure 9. Fall armyworm, note the inverted "Y" on the head.

Figure 10. Green cloverworm, note the three pairs of prolegs in the center of the body.

Both   FAW and GCW may be detected by sweeping or shake cloth samples. As they are foliage feeders, their impact on yield will be directly dependent on how much foliage they remove and what stage the plant is in during this defoliation. To determine the need for control you should refer to Table 2 in ENT- 13, Insecticide Recommendations for Soybean - 2009, which is available from your County Extension Office or on line at: http://pest.ca.uky.edu/EXT/Recs/ENT13-Soybeans.pdf .

In late season the most problematic insects are those that feed directly on the pods. Generally, these are the corn earworm and the stinkbugs (green and brown). These pests are problematic because of their direct damage to the pods and seeds and because they are harder to detect than the foliage feeders. The damage of the corn earworm is visible on the pod, while stinkbug damage often is not.

Figure 11. Corn earworm damage on soybean pods.

Figure 12. Green stinkbug.

Neither of the two insects does much damage to the leaves during the pod filling stages. So, in order to detect these pests, one must examine the pods directly. 

Using a shake cloth or direct examination, the economic threshold for corn earworm on soybeans is 2 CEW per row foot.  This work was done on 30” rows, so the number is likely higher on narrow rows or solid seeded beans. For stinkbugs you can use a 15” sweep net to make counts. The economic threshold for stinkbugs is 3 / 25 sweeps at growth stages R1-R3 or 9 stinkbugs per 25 sweeps from full pod to full seed. (R4-R6).

Bean leaf beetles will also feed on soybean pods. Most often they do little damage, but occasionally they will eat completely through the pod wall like corn earworm. When deciding upon the need to apply a control for corn earworms or stinkbugs, take into consideration whether or not bean leaf beetles are present. If either corn earworm or stinkbug populations are near economic threshold and bean leaf beetle feeding is present then the application is likely warranted.

Figure 13. Bean leaf beetle, not the black triangle directly behind the head.

In the case where insecticide applications are needed you will find suggested products in ENT- 13, Insecticide Recommendations for Soybean -2009, which is available at your County Extension Office or on line at: http://pest.ca.uky.edu/EXT/Recs/ENT13-Soybeans.pdf .

A recent visit to a Kentucky vineyard provided a reminder that crown gall is still a problem for many grape growers.  Crown gall is especially devastating to grapes in Kentucky and some vineyards have been lost due to the disease.  Crown gall can also affect other fruits such as apples, stone fruits, and brambles, but that crown gall bacterial strain is different from the one found in grapes.  There are more than 600 types of plants susceptible to crown gall diseases.  In grapes, Vitis vinifera cultivars are more susceptible to crown gall than V. labrusca cultivars.


Figure 14. Crown gall symptoms on a grapevine. Note the roughened, lumpy appearance along the trunk surface (J. Strang photo).


Figure 15. An individual large gall resulting from crown gall disease.


Figure 16. A vineyard with missing grapevines where crown gall has killed numerous vines.

Symptoms.  The disease is characterized by galls or knobby overgrowths that form on susceptible plant tissues, generally on grape trunks (Figure 14) at or above the graft unions.  Galls are rarely observed on the roots, but roots may develop necrosis.  New galls first appear in early summer as white, fleshy, callus-like growth.  Galls turn brown by late summer and in the fall become dry and corky.  The woody tumors may be gnarled with rough surfaces (Figure 15).  Galls can develop rapidly and completely girdle a young vine in one season, or they may take a few years to develop.  Galled vines frequently produce inferior shoot growth, and portions of the vine above the galls may die.  When galls are numerous they disrupt the translocation of water and mineral elements, from the roots to the top of the plant leading to poor growth, smaller and off-color leaves, gradual dieback, and sometimes death of vines (Figure 16).  In general, affected plants are more susceptible to adverse environmental conditions, especially winter injury.

Cause and biology of the disease.  Grape crown gall is caused by the soil-borne bacterium, Agrobacterium vitis, formerly thought to be a strain of Agrobacterium tumefaciens, the cause of crown gall in other fruit crops.  The bacterium survives at low levels for long periods of time in soil, and also in galls and in diseased plants.  The crown gall bacterium is widely present in Kentucky soils and may be systemically present in many grape vines, but the bacterium seldom causes disease unless the vine is injured.  Galls develop following an injury to grape cells permitting entrance of the pathogen into the plant cells.  Once inside the cells, crown gall bacteria induce the grapevine to produce galls through excessive cell division.  The initial cell injury permitting entry of crown gall bacteria often occurs as a result of intermittent freezing and thawing weather common to Kentucky each winter.  This kind of frequent freezing and thawing may not occur as much in other grape growing regions such as New York or California.  Overwintering bacteria may be spread to wound sites by splashing rain, running water, on cultivation implements, and on pruning tools.  Contaminated nursery stock may be another source of the disease.

Crown gall disease management. 

• Use disease tolerant cultivars.  In general, Vitis vinifera grapes are more susceptible than V. labrusca.  Highly susceptible cultivars include Baco Noir, Cabernet Franc, Cabernet Sauvignon, Chancellor, Chardonnay, Gewürtztraminer, Limberger, Merlot, Muscat Ottonel, Pinot Blanc, Pinot Gris, Pinot Meunier, Pinot Noir, Riesling, and Sauvignon Blanc.  Less susceptible cultivars include Catawba, Cayuga White, Concord, Cynthiana/Norton, Delaware, Einset Seedless, Foch, Fredonia, Ives, Mars, Steuben, Vanessa, and Ventura.
• Use crown gall resistant rootstocks.  Susceptible grapes on V. riparia or V. rupestris rootstocks may get less crown gall than those on V. vinifera.
• Select planting sites with no history of crown gall, or wait a few years before replanting such sites.
• Soil fumigation is generally not effective for destroying the crown gall pathogen.
• Plant the vineyard on northeast facing sites to help reduce freeze injury. 
• Plant vines in well drained soil.
• Minimize root injuries during planting.
• Plant only certified, disease-free nursery stock. 
• Discard plants with galls.
• Adopt management practices that minimize wounding.  Hill up soil around grapevines or otherwise protect the lower trunk in fall to reduce winter injury and resulting wound sites needed for infection.  Hilling also ensures the development of new scion shoots that may be needed for trunk renewal.  In some areas growers bury young vines in the fall to reduce freeze injury.
• Generally, remove and destroy infected plants, however, galls on the upper parts of the trunk or on canes can sometimes be pruned out.  A. vitis does not invade green shoots.
• Where feasible, apply Gallex (AgBioChem, Inc.), a crown gall eradicant paint derived from petroleum compounds.  This treatment is applied to already existing galls and following treatment, the galls gradually shrink and disappear.  Gallex only affects treated galls and will not stop nearby untreated galls.  Treatments may need repeating in future.
• The multiple trunk system of training may be a useful system for minimizing losses due to crown gall. If one or two trunks are infected, they can be removed.  The remaining trunks can be pruned leaving a full number of buds until more trunks can be renewed.
• Grape vines with poor vigor are more susceptible to winter injury, thus it is important to use proper pruning practices and leave proper crop loads for maximum vine vigor to result in stronger plants that are less susceptible to winter injury.  Manage other vine-weakening grape diseases such as downy mildew and powdery mildew so as to insure maximum vine vigor.

Figure 17. Lone star ticks have late burst of activity.


Figure 18. Lone star tick larvae (seed ticks) are tiny brown spots on pant leg. (Logan Miller photo).

The lone star tick is our most troublesome species based upon its frequency of attack on humans and animals; this is the time of year when they are at their peak (Figure 17). Anyone accidentally moving thru clusters of tiny, hungry seed ticks can face a miserable few days. Female ticks lay hundreds to thousands of eggs in clusters on the ground. The masses of 6-legged larval (or seed) ticks that emerge from these eggs climb vegetation and wait with front legs extended to latch onto a passing human or animal. They will wander on the skin for a time (in some cases up to 24 hours) before attaching to feed. Barbed mouthparts are inserted into the skin and a cement is secreted to hold ticks in place while they engorge, a process that can take from 2 hours to 7 days; then they drop from the host. Ticks inject an anesthetic material that makes the actual bite painless. However, the bite site may be red and painful for 1 to 2 weeks after the tick has fed.

Frequent, careful inspections are essential for those who are in situations that expose themselves to ticks. Here are some tips: 1) Look for movement of very small, freckle-like spots on clothing and skin – they may be seed ticks. The larger nymphs and adults are much easier to see. Wearing light clothing, especially pants, will make them easier to spot. 2) Avoid overgrown areas along trail edges or woods – ticks are more likely to occur there. 3) Use repellents or clothing treatments with permethrin when in areas where ticks are known to be active.

Ticks usually wander on people for some time before attaching. Regular inspections will help to catch them before this occurs. Also, it appears that infected ticks must feed for 24 to 48 hours before disease transmission occurs. More information on the lone star tick in Kentucky is available in http://www.ca.uky.edu/entomology/dept/entfacts.asp .