Cooperative Extension Service Taylor County 1143 South Columbia Avenue Campbellsville, KY 42718 (270) 465-4511 Fax: (270) 789-2455 www.taylor.ca.uky.edu

Taylor County

Horticulture Newsletter

October 2019

Upcoming Events: Monday, October 14th Busy Bloomers Garden Club 1:00 p.m. Thursday, October 17th Green River Beekeepers 7:00 p.m. Saturday, October 26th Clay Hill Critters 6:00 - 7:30 p.m. The Taylor County Farmers’ Market will be open every Saturday thru October 26th from 8:00 a.m. - 2:00 p.m. This is the last month to use senior vouchers. I hope to see you at these events! For more information or to RSVP to any of the events listed above, please call 270-465-4511 or stop by the Taylor County Extension Office. Thank You, Kara Back Extension Agent for Horticulture Education

Here are some things you can do to help your thirsty grass and hopefully avoid

having to completely reseed your lawn:

1. Water every other day or every third day until good, soaking rains begin.

2. Apply about two-thirds of an inch of water each time. You can check this by probing the soil with a knife or screwdriver to determine if the soil is wet 2 to 3 inches deep.

3. Water in the early morning to help reduce diseases, remove dew and reduce evaporative water loss.

4. Water areas that have the earliest browning first. These are often on southern or western facing slopes or areas with heavy clay soils, very compacted soil or rocks near the surface.

5. If possible, don’t mow a drought-stricken yard until you can water it or you know a soaking rain is on the way. Weeds are still growing and flowering during summer droughts. Wait for the rain, then mow off the weeds.

6. Don’t apply herbicides during a summer drought. They can damage drought-stressed grass more than weeds.

7. Wait for a soaking rain before applying nitrogen to the lawn in the fall. Nitrogen can greatly improve a lawn’s drought recovery.

Source: University of Kentucky Extension Specialist Gregg Munshaw

Corn Earworm Outbreaks in Industrial Hemp in Kentucky: September 2019 Helicoverpa zea (formerly Heliothis zea) is an insect that affects many crops and is known with different common names, depending on the crop it affects: cotton bollworm, soybean podworm, tomato fruitworm, or corn earworm. The larva of this noctuid moth is polyphagous and feeds on many other crops, including industrial hemp plants. Biology, and Description of Larva Female moths lay a single egg on suitable host plants. Once the egg hatches, first instar larva feed search and start feeding on beans in soybeans, kernels in corn, fruit in tomato or peppers, or buds and developing seeds in hemp. The larval instar is completed in 15 to 20 days depending on temperatures. Late instar larvae move into the soil to pupate. In Kentucky, one or two generations of corn earwoms can be completed every year. Larvae can reach up to 1.5 inch in length. The coloration of the larvae varies greatly ranging from green, pink, dark brown to almost black. There is a picture at the Purdue University- Exten-sion Entomology page that shows the different colors of corn earworms. In many hemp areas scouted for this report, the green

form is the most common (Figure 1).

Occurrence in Kentucky

Dr. Ric Bessin wrote that the abundance of the corn earworm in Kentucky’s sweet corn increases as the season progresses;

adult corn earworms (moths) migrating from southern areas especially affect sweet corn planted late. Thus, this coincides with

current observations in industrial hemp where this pest has been found feeding in hemp plants since late-August across several

areas of Kentucky. Unfortunately, this pest may become the key pest for the production of industrial hemp in Kentucky. Its

management in late planted sweet corn includes the application of insecticides every 3 to 5 days during the silking period.

However, the insecticides commonly used in corn (i.e. Bacillus thuringiensis, spinoteram, spinosad, or synthetic pyrethroids)

cannot be used in industrial hemp as they are not registered to be used in this crop.

Areas Scouted and Damage

During late August, only small size larvae were found in Caldwell and Lyon (Susan Fox) counties, whereas during the first two

weeks of September greater than 0.5-inch larval instars were found in the Caldwell, Graves, and Clinton counties. Larval instars

ranging from 0.5 to 1.5 inches in length were collected at Graves, and Caldwell counties.

Corn earworms are well camouflaged in the hemp shoots (Figure 2) and sometimes well-hidden deep within the hemp canopy

and tunnels it makes, but with a meticulous search, the worms can be easily found on plants. Damage of corn earworms can be

easily observed in hemp grown for CBD oil due to the frass (excrement from larva), tunneling on the buds, and wilting and death

of leaf and tissue surrounding the area of attack.

Management For the management of pests affecting hemp, the Kentucky Department of Agriculture is the entity responsible for regulating pesticide use in hemp. Currently there are few insecticide options to conduct foliar applications for corn earworms. The list of insecticides registered for hemp is in the KDA, and a previous publication in Kentucky Pest News summarize these pesticides.

For all pesticides registered in Kentucky it is necessary to follow all label guidelines.

Currently there are no guidelines to scout or tally for insects in hemp. However, during a collection of corn earworm in Caldwell

County for approximately 45 minutes, 15 worms were captured; and from this number, three larvae showed the presence of a

tachinid fly egg near the head, thus in this particular case 20% of larvae might have been potentially affected by this natural

enemy.

By Raul T. Villanueva. Extension Entomologist at Princeton, Samantha Anderson and Colby Guffey; Extension Agents for

Agriculture and Natural Resources at Graves and Clinton Counties, respectively.

R.T. Villanueva and C. Guffey

Raul T. Villanueva

Tree Wounds – Invitations to Wood Decay Fungi Wood decay leads to loss of tree vigor and vitality, resulting in decline, dieback, and structural failure.

Wounds play an important part in this process since they are the primary point of entry for wood decay

pathogens. While other factors may also result in decline and dieback, the presence of wounds and/or

outward signs of pathogens provides confirmation that wood decay is an underlying problem. Wounds and

wood decay reduce the ability of trees to support themselves.

Wounds may result from numerous sources such as lawn equipment (Figure 1), pruning, vehicles, herbi-

cides, insects, wildlife, weather, or objects that girdle or embed in trunks or branches (Figure 2). Once stress

or damage from wounds occurs, fungal decay pathogens may enter plants to cause further damage. During

rainy seasons and moderate temperatures, many wood decay fungi produce visible reproductive structures,

such as shelf-like fungal bodies (Figure 3) or mushrooms.

Additional Information Tree Wounds – Invitations to Wood Decay Fungi (PPFS-OR-W-01)

Plant Pathology Publications (Website)

By Kimberly Leonberger, Extension Associate and Nicole Ward Gauthier, Extension Plant Pathologist

Taylor County 1143 South Columbia Avenue Campbellsville, KY, 42718 RETURN SERVICE REQUESTED