P. 1,2,4 CORN DISEASE UPDATE: TIME FOR FOLIAR FUNGICIDE APPLICATION DECISIONS IN CORN

P. 3-4 W. KY SUMMER FORAGE TOUR: FINISHING AND MARKETING LIVESTOCK ON GRASS

P. 5 PROTECTING YOUR CUCURBITS

P. 6  CONGRATS IT'S A BABY BAGWORM

P. 7 SUPPLEMENTING TO STRETCH PASTURES

P.8 BLACKBERRY GRILLED CHEESE

IN THIS ISSUE:

Nikki's NEWSLETTER

The July 2020 Edition of:

GRAIN CROPS

FORAGES

HORTICULTURE

LIVESTOCK

RECIPE OF THE MONTH

Cooperative Extension ServiceUniversity of Kentucky 

Marshall County 1933 Mayfield Highway 

Benton, KY 42025(270) 527-3285

extension.ca.uky.edu

We are still in phase 2 of reopening. Here's the "skinny" on what that means:We are still open for regular business hours from 8-4:30 M-F. You will still need to sign in when entering the building for contact tracing purposes. We are still limited to 50% or less staff in the office daily.Nikki's office phone and voicemail are still being forwarded to my cellphone. Educational programs are still limited to web based meetings except for small meetings of 18 people or less that are considered necessary.

***On July 10 the Governor has issued an executive order that requires face masks when in public. This new executive order means that our program participants must wear face masks to participate in our programs unless they have a health condition that prohibits their use. Thank you for your cooperation during these tough times. Corn is moving through growth stages quickly, and the warm, humid weather in many parts of Kentucky has been conducive for foliar disease development. Fungicides are commonly promoted to reduce the impact of foliar disease in corn, but with tight margins and a difficult market, it is important to pay careful attention to the factors that influence the profitability of a fungicide application.Factors to Consider: (1) Crop production factorsCheck hybrid ratings for foliar diseases, such as gray leaf spot, prior to fungicide application. Fungicide applications to hybrids with good foliar disease resistance are less likely to provide economic returns. Hybrids susceptible to foliar diseases are more likely to respond to foliar fungicides, especially if planted in continuous corn or fields under conservation tillage. These fields are at higher risk for foliar disease development since the fungi that cause several foliar diseases survive in residue. Additionally, irrigated fields are at higher risk for foliar diseases since irrigation creates an environment favorable for disease development. (2) Fungicide timingUniversity research indicates that foliar fungicides applied at tasseling or early silking (VT-R1) provide optimal foliar disease control and also the best chance for seeing a yield response, compared to applications that occur after ‘brown silk’ (R2) for most foliar diseases in corn. Early vegetative stage applications are less likely to provide an economic return, and applications that occur at brown silk or later may be too late to realize the full benefit of the fungicide application for diseases like gray leaf spot. Continued on page 2

Update from the Marshall County Extension Office

Marshall County’s Agriculture and Natural Resources Update

By Kiersten Wise, Plant Pathology Extension Specialist

Corn Disease Update: Time for Foliar Fungicide

Application Decisions in Corn

2

(3) Fungicide classRecent University research indicates that fungicide class influences the potential for yield response from foliar fungicide applications occurring at VT (link). Applications of products containing both strobilurin (QoI; FRAC group 11) and triazole (DMI; FRAC group 3) fungicide classes are more likely to result in a positive return on fungicide investment compared to applications of products containing only a strobilurin or triazole fungicide active ingredient. Fungicide classes and efficacy of specific fungicide products for foliar diseases like gray leaf spot are described in the updated fungicide efficacy table for management of corn diseases, which is developed by the national Corn Disease Working Group and posted on the Crop Protection Network website. (4) Yield potential in damaged cornFlooding, hail damage, and other weather events have reduced corn yield potential in certain fields in Kentucky. Before applying a fungicide to these fields, assess yield potential and determine if additional investment in the crop is warranted. Remember that fungicide applications are most successful when used to help protect yield from foliar diseases. Fungicide applications used to ‘recover’ yield in a compromised crop may be less economically viable. (5) Disease identificationIt is important to accurately identify foliar diseases before deciding if a fungicide application is needed. There are several diseases appearing across Kentucky, some of which do not warrant fungicide application. The most common corn diseases observed over the last week are described below. Corn Leaf Spot Diseases:Gray leaf spotGray leaf spot (GLS) is caused by the fungus Cercospora zeae-maydis. Early symptoms are observed on leaves as tiny lesions surrounded by a yellow halo. It is difficult to diagnose GLS when the lesions are very small, but these lesions will elongate into narrow, rectangular, brown to gray spots, expand parallel to the leaf veins, and may grow to over 1-inch-long on susceptible hybrids (Figure 1). Symptoms vary depending on hybrid susceptibility, and hybrids with some level of resistance to GLS may only have small, jagged lesions rather than the long, rectangular shape characteristic of lesions on more susceptible hybrids. The fungus that causes gray leaf spot survives the winter in residue, and typically lesions are first observed on the lower leaves and move up the canopy as the season progresses. Diplodia leaf streakDiplodia leaf streak, caused by the fungus Stenocarpella macrospora, can be confused with gray leaf spot in the early stages of development. Small, elongated lesions appear on leaves (Figure 2), sometimes in the mid-canopy, which can help distinguish it from gray leaf spot (the latter typically appears in the lower canopy and progresses into the mid-upper canopy). The lesions will expand over time into streaks that are several inches or more long. Small black fungal structures may be visible in the center of the elongated lesions. Diplodia leaf streak is a disease that has recently become more prominent in corn, and the link between disease and yield loss has not been established. Currently, there are no fungicides labeled for Diplodia leaf streak. The fungus that causes Diplodia leaf streak survives in residue and therefore rotation or residue management can help reduce disease in future years. More information on Diplodia leaf streak can be found in the UK Extension publication, Diplodia Leaf Streak (PPFS-AG-C-08). Holcus leaf spotHolcus leaf spot is very common in Kentucky corn this year. Holcus leaf spot is a disease caused by the bacterium Pseudomonas syringae pv. Syringae. It is characterized by round, discrete lesions that are initially pale yellow to white and then enlarge and turn gray or brown. Lesions have a water-soaked halo, and on certain hybrids, the margin of the lesion may appear brown or purple (Figure 3). Holcus leaf spot is not known to limit yield. Although the disease may cause concern based on symptom appearance, no in-season treatment is available or necessary. Fungicide applications will not have efficacy against this bacterial disease. More information on this disease can be found in the UK Extension publication, Holcus Leaf Spot (PPFS-AG-C-06). Curvularia leaf spotCurvularia leaf spot is also very common in Kentucky this year and can be confused with holcus leaf spot and gray leaf spot. Curvularia is a relatively new disease in Kentucky, caused by the fungus Curvularia lunata. Small, tan to pale yellow lesions can be observed on the leaf, and the lesions are often surrounded by a brown or tan halo (Figure 4). Curvularia is not thought to consistently limit yield, and no fungicides are labeled for the disease at this time. More information on Curvularia leaf spot can be found in the UK Extension publication, Curvularia Leaf Spot (PPFS-AG-C-09). Continued on the bottom of page 4

1

2

3

4

5

6

3

4

Corn Disease Update- Continued from page 2 Common RustCommon rust of corn, caused by the fungus Puccinia sorghi, has been observed in a few fields in Kentucky this year. The fungus that causes common rust produces brown to brick-red pustules that are present on upper and lower surfaces of the leaves (Figure 4). Young leaves are more susceptible to rust infection than mature leaves. In most years, common rust does not require management in hybrid field corn in Kentucky, and the greatest concern is that common rust is accidentally confused with the more damaging disease southern rust. Southern rust (not currently in Kentucky)Southern rust of corn, caused by Puccinia polysora, has been a concern of farmers for the last few years. This disease is characterized by orange pustules that form on the upper surface of the corn leaf (Figure 6) The fungus that causes this disease does not survive winters in Kentucky, but moves north each year from Mexico and states in the southeastern U.S. As of July 6, 2020, southern rust has been confirmed in a few counties and parishes in Georgia, Louisiana, Mississippi, and Texas. If corn can reach milk stage (R3) before southern rust appears in Kentucky, there is likely to be little-to-no impact on yield. Real-time monitoring of southern rust can be observed by checking this website.

5Protecting your Cucurbits

Ric Bessin, Extension Professor, UK Department of EntomologyThey may not bear a family resemblance, but cucumbers and pumpkins are closely related. They are cucurbits, a family that includes other popular garden plants such as zucchini, summer squash, winter squash, cantaloupe and watermelons. They all tend to take up a lot of room in the garden, so if you’re going to dedicate that much space you’ll want to reap as much fruit as you can. Yes, botanically, these are fruits, though we include many of them in our meals as vegetables.The problem with cucurbits is that we’re not the only ones who enjoy them. Between insect pests and bacteria, plants in this family attract a lot of troublemakers. Striped and spotted cucumber beetles are the most common insect pests on all the cucurbits and will cause significant damage to seedlings and ripening fruit. They also transmit the bacterium that causes bacterial wilt, which hits cucumbers and melons particularly hard. Gardeners can be taken by surprise when wilt attacks; in the morning the plant can look healthy, but by evening a runner and its leaves have wilted irretrievably.

The best time to manage this problem is immediately after planting by applying a one-time soil drench of a systemic insecticide, which should provide three to five weeks of control. But if you didn’t apply the insecticide at planting, it’s still worth your time to scout for beetles and apply foliar insecticides as necessary to protect susceptible plants, particularly close to harvest. If you only have a few plants in your garden, picking off beetles by hand is another option, though you may have to do it daily, and it’s not a guarantee against wilt.

Squash beetle is a large lady beetle with 12 black spots on its back and an orange thorax. Whereas some lady beetles are beneficial and feed on pests like aphids, the squash beetle feeds on the underside of leaves, skeletonizing them, and can be a serious pest of squash and pumpkin. Apply foliar insecticides as necessary during the mid- and late season.

Then there’s the squash bug, which is brown and about 1-inch in length. They appear starting in June. They damage plants by dining on the sap, as well as causing leaves to wilt and collapse. Most detrimental, though, is that they carry the bacterium for yellow vine decline, which affects melons, watermelon and pumpkins. Foliar sprays targeting newly hatched nymphs are more effective than sprays used against the later stages of the insect. You may need to spray multiple times throughout the course of the growing season.

Keeping your cucumbers from having direct contact with the soil can prevent belly rot. When a cucumber lies directly on the soil, it can develop tan or brown lesions that resemble a dry rot. Using mulch as a barrier between fruit and soil helps. Also be careful not to overwater; overly wet soils can add to the problem.

With a little care, your homegrown cucumbers, squash and melons will thrive and give you a bountiful harvest and enrich your table.

For more information about cucurbit diseases and pests, check out the University of Kentucky Cooperative Extension publication, ID-128, Home Vegetable Gardening, http://www2.ca.uky.edu/agcomm/pubs/id/id128/id128.pdf, or contact the Marshall County Office of the University of Kentucky Cooperative Extension Service.

6

By Jonathan L. Larson, Entomology Extension Specialist

Daffodils

Bagworm season is upon us in Kentucky. Depending on where you live, the hatching could have occurred anywhere from just in the last few days to a couple of weeks ago. If you want to monitor for their emergence next year, you can use this handy emergence map made through the National Phenology Network.

Description, Damage & HostsAs adults, bagworms are moths, but the destructive stage is the caterpillar. Unlike other caterpillars that you can see out in the open and feeding, the bagworm wears a tactical stealth sleeping bag that helps to camouflage it. The caterpillar creates the bag from silk it can produce itself and from the materials they find in their surroundings. This means that they can have pine needles, cut off chunks of leaves, even fruiting bodies attached to the bag (Figure 1). Some clients that spot the bag are confused at the number of pinecones or seed pods in their tree, not knowing their plant has been invaded. Bagworms are most commonly found in evergreen trees and shrubs but also can infest deciduous trees. Some favorite hosts are arborvitae, juniper, pine, red cedar, and locust trees. Their damage causes defoliation but also bronzing in evergreens. While bagworm damage in one season is not usually enough to kill a plant, successive years of infestation and damage can prove deadly.

Insect DevelopmentBagworms overwinter as eggs inside of their mother’s bag. As the season progresses, the eggs accumulate degree days. Every day at or above a certain temperature counts as a degree day or days towards hatching. Once they reach their magic number (between 600 and 900 growing degree days), the eggs will hatch. After this, the caterpillars might re-infest the same plant that they were born in or they may “balloon” away to a new site. This means the caterpillar will crawl to the tip of a leaf and release a silk strand that catches the wind to help it find a new place to settle. Kite surfing baby caterpillar pioneers could have whizzed by you very recently! Their bags start small as you can see in Figure 2, but if you are paying close attention in spring, you can spot them.

As the summer progresses, bagworms will consume leaves around them to expand their bag. Eventually the bag will reach about 1.5 to 2 inches long. The caterpillar can be seen poking its head out of the bag and feeding (Figure 3). If disturbed, it will withdraw inside the bag and are difficult to extract. By the end of the summer, the caterpillar will pupate and males will emerge as moths that flutter around looking for females. Females never fully become what we recognize as a moth. They are wingless and never leave the bag. They release a pheromone that attracts the males to them so mating can occur through the opening of their bag. Then females lay their eggs and perish.

ManagementManaging bagworms is easiest at this point in the season.- If you notice the bags or know that you have a tree that was infested last year, you should consider purchasing a Bt-based product to control the young caterpillars. This is an organic option and very effective against caterpillar pests if used against the early instars.

Congrats, It’s a Baby Bagworm!

Figure 3: A bagworm caterpillar feeding outside of its bag. The yellow arrow is pointing at its head. This specimen is from later in the season, early August, and is larger than the bagworms you would encounter now. (Photo: Jonathan Larson, UK).

Figure 2: Newly emerged bagworms are small and so are their bags. These caterpillars may either infest the plant they were born on or they balloon away to a new location. (Photo: Jody Green, Nebraska Extension).

Figure 1: Bagworm bags are constructed out of what they find in the plant they have infested. This means that different bags from different trees can have distinct appearances. (Photo: Jonathan Larson, UK).

- Other options include Spinosad and neem. If you miss this early window for control, the problem will be harder to deal with later in the season. If you catch this in late July or August then you will have to resort to using a bifenthrin, carbaryl, or cyfluthrin product. You can also wait until fall/winter and remove the bags by cutting them off the twig with a pair of shears and destroying the bagworm in soapy water. This will reduce the number of caterpillars that emerge the next year.

7

Jeff Lehmkuhler, PhD, PAS Associate Extension Professor, UK

Daffodils

Drought continues to impact the high plains area stretching down to the pan handle of Texas. The dry conditions will continue to impact pastures potentially lowering beef cattle numbers at year’s end. The recent high temperatures and limited rain will dry out pastures and limit forage regrowth on recently cut hay fields here in the Commonwealth. As forage growth slows, supplementation may be needed to provide beef cattle adequate levels of nutrients to support target production levels and limit condition loss of lactating cows. Fibrous coproduct feedstuffs that are low in starch but high digestible fiber work well for supplementing cattle on a high forage diet. Soybean hulls, corn gluten feed, beet pulp, distillers grains, wheat midds, and rice bran are a few commonly available feedstuffs that would be lower in starch and high digestible fiber. These feedstuffs would be higher in available energy than most pasture forages that are going or already dormant. Depending on the maturity and digestibility of the forages, supplements could provide twice as much energy on a dry weight basis. Therefore, supplementation would need to be limited and not offered free-choice to avoid over conditioning as well as to avoid digestive upsets. Cottonseed hulls are lower in digestible energy than the supplements listed above and most cool-season forages. Cottonseed hulls would be deemed as more of a forage replacement than a supplement. The crude protein value is low ranging from 4-6% typically and the protein is relatively low in digestibility. The acid detergent value is reported to be high, near 65%, leading to a relatively low calculated Total Digestible Nutrient (TDN) value ranging 34-42%. Work at North Carolina has shown that self-fed diets containing 30% cottonseed hulls are effective for developing 2-6 month old dairy heifers. Many commercial precondition and creep feeds contain cottonseed hulls as a fiber source. The price of cottonseed hulls can be a limitation for their utilization. Having a nutrient content lower than typical fescue hay, the price paid should be similar or less than what one would pay for hay. Starch containing feedstuffs such as wheat, barley, corn and oats are available to supplement energy to grazing cattle. Due to negative associative effects in the rumen when feeding starch supplements to cattle consuming a predominate forage-based diet, these feedstuffs should be limited if one wishes to avoid lowering fiber digestibility. Previously, summaries of supplementation research would indicate that offering 0.3% of body weight or less would minimize negative associative effects of starch supplementation. This would be equivalent of approximately 3-3.5 pounds of corn per 1,000 pounds of body weight. Supplementation with starch containing feeds can lead to a decrease in ruminally available nitrogen and amino acids needed by the microbes on low quality forage diets. Therefore, to mitigate negative associative effects protein supplementation may be necessary. Other researchers have demonstrated that providing protein supplementation with starch containing feedstuffs, levels as high as 6-8 pound/1,000 lb of body weight have had minimal impacts on fiber digestion. Providing supplementation to cattle grazing pastures, the impact on forage intake will be dependent upon associative effects that may occur in the rumen. Providing protein to correct a ruminal nitrogen source deficiency may enhance fiber digestion and increase dry matter intake having a positive impact.  Supplementing with excessive starch and reducing rumen pH and limiting available nitrogen sources for microbes will lead to lower intakes. In general, forage and supplement exchanges often average 2-3:1 in which forage intake decreases 2-3 pounds for each pound of supplement consumed at lower levels of supplementation. There is a wide degree of variability in the actual forage intake response and one should monitor cattle and observe body condition to ensure sufficient nutrient intake to support the desired level of performance. If you are faced with limited pasture forage or hay, consult with your nutritionist or county Extension agent to develop a feeding program for your herd. There are many feedstuffs that can be utilized to develop the most cost-effective feeding program that delivers the nutrients the cattle need to achieve your desired level of performance. Here’s hoping you all get some timely rain.

Supplementing to Stretch Pastures

For more information go to:http://marshall.ca.uky.edu/AgNaturalResources

or follow us on Facebook @marshallcountyextensionanrMarshall County Extension

Agent for Agriculture and Natural Resources

Educational programs of Kentucky Cooperative Extension serve all people regardless of economic or social status and will not discriminate on the basis of race, color, ethnic origin, national origin, creed, religion, political belief, sex, sexual orientation, gender identity, gender expression, pregnancy, marital status, genetic information, age, veteran status, or physical or

mental disability. UNIVERSITY OF KENTUCKY, KENTUCKY STATE UNIVERSITY, U.S. DEPARTMENT OF AGRICULTURE, AND KENTUCKY COUNTIES, COOPERATING