Andrew Kness, Senior Agriculture Agent | akness@umd.edu and Erika Crowl, Senior Agriculture Agent Associate University of Maryland Extension
Orchardgrass is a popular pasture and hay forage species and it requires relatively high fertility levels, especially in a hay system where nutrients are being exported from the field. To test and demonstrate the importance of potash (potassium) fertility in orchargrass plantings, we established a replicated trial at the Western Maryland Research and Education Center. Three orchardgrass varieties were planted in a prepared seedbed at a seeding rate of 22 lbs pure live seed per acre using a drop-seeder on September 27, 2021. Plots were 6 feet wide by 20 feet long. Each variety received three fertility treatments: 1.) 0 lbs/A potash, 2.) 45 lbs/A potash (based on soil test), or 3.) 200 lbs/A potash, based on the potassium removal rate of 4 ton/A orchardgrass yield.
On March 23, 2022, 50 lbs/A nitrogen and 20 lbs/A phosphate (based on soil test) was top dressed to all plots. On April 8, 45 lbs/A potash (0-0-62) was top dressed on the 45 lb/A plots and 200 lb/A plots.
First cutting was done on May 23 using a small-plot forage harvester from the center 3 feet of each plot (Figure 1). Each plot was weighed and moisture subtracted to calculate dry yield. Following the first cutting, all plots received 50 lbs/A nitrogen in the form of urea and 75 lbs/A potash was top dressed on the 200 lbs/A plots.
Figure 1. Orchardgrass harvest.
Second cutting was performed on July 13 as described above, followed immediately by 50 lbs/A nitrogen. The third and final cutting was performed on September 16. Final fertilization of 80 lbs potash added to the 200 lbs/A plots and 50 lbs/A nitrogen was added to all plots on September 23.
Yield data was compiled and analyzed in JMP statistical software package, differences were separated using Fisher’s Least Significant Difference (α=0.10).
Interestingly, Potomac, an old variety, yielded significantly more (3.96 tons/A) than Olathe (3.65 tons/A) and Rushmore II (3.67 tons/A). In terms of fertility, plots that received 200 lbs/A potash yielded significantly more than those that received 0 and 45 lbs/A (Table 1).
Figure 1. Average orchardgrass cutting yield by variety and potash treatment.
We will continue this project in the coming years to collect more data and see how potassium fertility affects persistence and yield over the long term.
This work was supported by the Maryland Horse Industry Board and the University of Maryland AgFS Program. Special thanks to the Maryland Agriculture Experiment Station and the farm crew at the Western Maryland Research and Education Center.
Table 1. Orchardgrass yields in 2022 plots.
Potash Fertility
Average Yield/Cutting (Tons/A)
Combined Yield (Tons/A)
0 lbs/A
1.23 az
3.71 a
45 lbs/A
1.22 a
3.65 a
200 lbs/A
1.30 b
3.91 b
p-value
0.0328
0.0325
z Means followed by the same letter are not significantly different based on Fisher’s Least Significant Difference (LSD; α=0.10).
Amanda Grev, Pasture and Forage Specialist University of Maryland Extension
As new forage varieties continue to be developed and released, the efficacy and performance of these varieties needs to be evaluated. Similarly, as forage and livestock producers are making decisions on which forage species and variety to establish, it is helpful to compare performance data from a number of available varieties. To this end, the University of Maryland Extension Forage Team is in the process of establishing a series of forage variety trials.
In September 2019, an orchardgrass variety trial was established at the Western Maryland Research and Education Center (WMREC) in Keedysville, MD in order to evaluate select orchardgrass varieties based on forage production and quality. Plots were arranged in a randomized complete block design with each individual entry replicated four times. All varieties were planted at a rate of 25 pounds per acre; seed was broadcast and then cultipacked to establish good seed-to-soil contact. The varieties planted included: Alpine, Bounty II, Extend, HLR Blend, Inavale, Olathe, Pennlate, and Rushmore II.
Data collection began when the majority of forage varieties reached the boot stage of development (prior to seed head emergence). The first cutting occurred on May 18, 2020; this was followed by a second cutting on August 3, 2020 and a third and final cutting on September 28, 2020. At each cutting, forage biomass was collected along a 3 ft. by 20 ft. strip from the center of each plot using a forage harvester set to a cutting height of 4 inches. Collected biomass was weighed, dried in a forced air oven, and weighed again for dry matter and forage yield determination. Sub-samples were also taken from each plot and sent to a commercial laboratory for forage quality analysis.
Seasonal cumulative yield for all orchardgrass varieties ranged from 3.6 to 3.8 tons per acre (Figure 1). Statistical analysis indicates no significant difference in forage yield among any of the varieties for the 2020 growing season. Forage quality analysis is underway; forage quality results will be shared once the analysis is complete.
A big thank you to Jeff Semler and the entire WMREC crew for their assistance in getting this trial started and their help with harvest and data collection. Seed for this study was donated by DLF Pickseed, Seedway, and Kings Agriseeds. These plots will continue to be evaluated for yield, quality, and additional performance parameters in the coming years. We hope to expand the trial to include multiple locations, as well as additional forage species and varieties.
Figure 1. Orchardgrass forage variety trial yield results for 2020, presented as total seasonal yield in tons per acre. Varieties marked by a common letter indicate similar yield production (i.e. no significant difference).
Kelly Hamby, Terry Patton, and Galen Dively Department of Entomology, University of Maryland College Park
Summary. Weather stations in Baltimore, MD recorded the 3rd warmest winter on record in 81 years from Dec 2019 to February 2020, with 10% of our 30 year average snowfall (NOAA National Climate Report). Insects that overwinter as immatures or adults in above-ground protected areas are typically favored by mild winters, especially species that are not cold-hardy because much of the population would typically die during the winter. However, the lack of snowfall can also reduce overwintering survival because snow can insulate against freezing temperatures. Mild winter conditions favor green bug aphids and winter grain mite outbreaks in small grains and orchardgrass, and these pest populations can build rapidly. Fortunately, mild winters also favor many beneficial natural enemies. Greenbug aphid outbreaks have been observed in central Maryland orchardgrass (see Figure 1), and greenbugs have also been observed in Delaware. Overall, aphid populations have been spotty in Delaware and promising natural enemy activity has been observed (UD Weekly Crop Update, March 20). However, close surveillance is necessary when greenbug is the predominate species because greenbug injects toxic saliva during feeding and can be very destructive. It is important to carefully scout your fields for aphids multiple times to determine whether populations are building or crashing on your farm. Management interventions may be necessary to prevent economic losses. Winter grain mites may also be a problem this year and scouting close to the soil surface is necessary to catch this issue in a timely manner.
Figure 1. Heavy aphid populations have been observed in orchardgrass in central Maryland.Figure 3. Aphid damage to orchardgrass in central Maryland.
Cereal Aphids and Greenbugs. Multiple species of aphid occur in Maryland small grains and orchardgrass (see Figure 2) and aphids can vector barley yellow dwarf virus. Bird-cherry oat aphids vector the most severe strain and may need to be managed in the fall to prevent damage from barley yellow dwarf, especially in intensive management wheat. Although the direct damage from aphid feeding is generally similar across species, it is especially important to record species if greenbugs are present. Greenbug saliva contains enzymes that break down cell walls, so their feeding is most damaging. They initially cause spotting on the leaf followed by discoloration and eventual leaf and root death if feeding continues. Grain cultivars vary in their tolerance for greenbug damage. One of the first noticeable symptoms of aphid outbreaks are circular yellow to brown spots with dead plants in the center (see Figure 3); however, aphid damage may be confused with moisture stress and/or nitrogen deficiency so make sure to scout for aphids especially in areas that are showing stress symptoms. Scout a minimum of 1 linear row foot in 10 sites, the more row feet and locations the better, and estimate the number of aphids per foot of row. The rule of thumb treatment threshold for small grains is to treat if counts exceed 150 per linear foot throughout most of the field, with few natural enemies detected (e.g., mummy aphids, lady beetles, fungal infections). One natural enemy to every 50 to 100 aphids can be enough to control the population. This threshold may be lower if greenbugs are the predominant aphid and greenbug populations should be carefully monitored. Foliar insecticides including pyrethroids (Group 3A), neonicotinoids (Group 4A), and organophosphates (Group 1B) can be used to control aphids.
Figure 2. Common cereal aphids. Notice color and length of antennae and cornicles (tail pipes). Greenbugs are light green with a dark green stripe, with black tips of the legs, cornicles, and antennae. Photos: Various Extension websites.
Winter Grain Mite. Winter grain mites are a cool season pest of small grains and orchardgrass that cause a silvery leaf discoloration from feeding damage that punctures individual plant cells. Feeding can also stunt plants. Winter mites have a dark brown to black body with bright reddish-orange legs (see Figure 4). Somewhat uniquely, their anal opening is on the upper surface and can appear as a tan to orange spot that is more visible under magnification. Two generations of winter grain mite occur per year and are active from the fall to early summer. They oversummer in the egg stage, with the first generation hatching around October and adult populations peaking in December or January. The second generation peaks from March to April and produces the oversummering eggs. Because spring eggs result in fall populations, rotating the crop away from grasses and managing wild grasses around field edges can be helpful to reduce populations. Adult activity occurs when temperatures are between 40 and 75°F, and they prefer cool, cloudy calm weather. Therefore, winter grain mites are easier to see during these conditions, and more likely to be higher on the plant during the early morning or late evening. If you are scouting on a hot, dry day or in the middle of the day, you should check under residue where the soil is moist, and may need to dig 4 or 5 inches into the soil to find the mites. Winter grain mite does not typically cause economic damage, and no thresholds have been developed. If large portions of a field show symptoms and mites are present, treatment may be warranted. No products are specifically labeled for winter grain mite; however, products labeled for brown mite such as dimethoate (Group 1B, in wheat only) are likely to be effective. Warrior II (pyrethroid, Group 3A) may also provide suppression.
