It may seem early to start thinking about your rice pest control program. But planning ahead could be critical, according to some rice specialists who have seen the damaging effects of grape colaspis, a pest that may only be controlled at planting time with an insecticide seed treatment. Often misidentified as seedling disease or soil problems, grape colaspis can cause stand reduction, delayed rice plant development and impeded uniformity.
“The above-ground symptoms of a grape colaspis infestation can be confused with a lot of things,” says John Bernhardt, Rice Research and Extension Center, University of Arkansas, Stuttgart, Ark. “The plant is sickly looking, stunted in growth and yellowish. Infestations can result in a thin stand where some plants do not even emerge. The damage is caused by overwintering larvae feeding on germinating seeds or seedlings when rice is rotated after a legume crop such as soybeans, lespedeza or clover.”
The grape colaspis, commonly called the lespedeza worm, has been one of the toughest to manage and identify since damage occurs below the soil surface during the seedling stage, and the larvae may be gone before the damage symptoms are noticed.
Treating for grape colaspis
Research conducted by John Bernhardt in 12 grower fields during 1999 showed that Icon insecticide seed treatment prevents damage from grape colaspis. Damage from grape colaspis was found in all of the fields, but much more damage was detected where untreated seed was planted. Seedlings in areas that were planted with Icon-treated seed had no visible signs of stand loss.
“You could see to the row that the damage ended where use of Icon-treated seed started. We had quicker emergence and better stands,” Bernhardt says.
Flooding rice fields may dislodge some larger larvae, but it is doubtful that flooding provides sufficient control. No effective insecticidal control is available for grape colaspis, besides planting rice seed treated with Icon. In addition to controlling rice water weevil, seed midge and rice borers, Icon has recently been labeled for the control of grape colaspis.
Grape colaspis has reportedly been a problem since the mid-1800s, when it drew the attention of economic entomologists for damaging grape foliage and earned its name. Through the years grape colaspis has been observed damaging strawberries in Missouri, pecans in Florida, cotton in Louisiana, and a host of other crops in different geographies.
Jim Robbins of Mississippi State University, Stoneville, Miss., will be testing for grape colaspis on rice this coming season. He believes that grape colaspis has probably been misdiagnosed in Mississippi over the last 10 years, and he has seen more occurrences of what he believes to be grape colaspis over the last two years.
Marvin Lott at Jimmy Sanders, Cleveland, Miss., believes grape colaspis may be a problem in his area, as well. He has conducted research for the past two years on Icon on grower fields. Whether results are attributed to Icon's control of rice water weevil, grape colaspis or other pests, Icon-treated fields have shown a visible height difference and healthier root mass, says Lott.
“We think grape colaspis has been a problem in the past, but we've just not been aware of it. We thought it was seedling disease,” Lott says. “Using Icon, we see a healthier plant. It emerges better. When planted on the same dates, the Icon-treated rice comes up three to four days quicker. We've seen this for the past two years.”
Identifying grape colaspis
Specialists Bernhardt, Robbins and Lott say that if a grower sees above-ground symptoms, he should dig up the plant from the soil and look at the area of the stem between the seed and the soil surface called the mesocotyl. If help is needed to identify the problem, growers should keep the soil around the roots moist and fresh, and take it to a county agent to look for the larvae. The larvae are dirty, white grubs as large as 3/8 inch long, with three pairs of legs near the head.
Rice in rotation after soybeans or other legume crops may have seedlings killed soon after germination by the larvae. Adults lay eggs in the legume hosts. The larvae feed on the roots and overwinter in the soil. The small, white grubs move to the soil surface as the soil warms the following spring and eat into rice stems just above the seed.
“Grape colaspis larvae will feed on that part around the stem, removing layers or girdling the mesocotyl until there is only a threadlike portion left,” says Bernhardt. “The larvae very rarely sever the mesocotyl, but the damage prevents uptake of water and nutrients. Once girdled, if plants are under any type of stress, they have a tendency to die.”
In one highly infested field in Ashley County, Ark., Bernhardt found only 10 plants lived in an area 10 feet by 10 feet. In the Icon-treated portion, Bernhardt counted 40 to 50 healthy plants per square foot.
“I saw a remarkable difference in plant stand and uniformity between the Icon-treated rice and untreated rice in plant stand and uniformity, which can be attributed to the grape colaspis,” says Bernhardt. “The Icon rice jumped out of the ground a day or two before the untreated. Those untreated plants that survived were not uniform.”
According to Bernhardt, grape colaspis impacts a grower's crop in two ways. First, it can reduce stands. If stand loss is not severe, other plants can compensate and it's hard to see an economic impact. However, grape colaspis can impact the crop in a second way. All damaged plants may not die, but they will be delayed. The crop will not be uniform, making the rest of the crop very difficult to manage.
If you've identified grape colaspis as a problem on your farm, you can plan for it by using Icon-treated seed, as well as treat for rice water weevil, seed midge and rice borers. If you're unable to take the preventive measures of using Icon seed treatment at planting, specialists suggest that plants should be kept well-watered. Plants that are already damaged by grape colaspis should not be allowed to get water-stressed.
“You're going to lose plants anyway, but you'll lose more to water stress,” says Bernhardt. “Flushing often improves the situation but may not be enough to prevent significant stand loss in cases of heavy infestation and severe damage.”
Marketing Group Selling New Soybean Variety - CAVINESS
Ag Genetics of Arkansas, a non-profit corporation, has been licensed by the University of Arkansas Division of Agriculture to market the new high-yielding soybean variety named “Caviness”.
Ag Genetics of Arkansas is a marketing group open to any qualified seed dealer or grower. Twenty-six Arkansas seed dealers are charter members, and 21 of those were licensed to market Caviness certified seed for planting in 2001.
Greg Weidemann, associate director of the Arkansas Agricultural Experiment Station, said the Ag Genetics charter preserves the features of UA crop varieties that are important to producers.
“Farmers contribute Soybean Promotion Board checkoff funds to help support the UA breeding program,” Weidemann said. “We were very careful to put the farmers' interest first in this process. We insisted on several things in the marketing group.”
Farmers will be allowed to save seed of the Caviness variety for planting on land they farm.
The group is open to any qualified seed dealer or grower. Members will contribute to an AGA marketing fund, and a foundation seed fee will be collected on each bag of certified seed to help pay for the production of genetically pure foundation seed by the U of A Division of Agriculture.
Only “blue tag” certified seed inspected by the Arkansas Plant Board will be sold.
Ag Genetics members bought more than 9,800 fifty-pound bags of Caviness foundation seed in 2000. That's more than all of the foundation seed varieties combined sold in recent years. Growers will have no trouble finding Caviness seed for planting in 2001.
The average yield for 2000 was an impressive 67.1 bushels per acre at the Rice Research and Extension Center at Stuttgart, AR and the 2-year average yield was 66.2 bushels per acre.
The high-yield potential of Caviness was proven not only in University variety trials in Arkansas, but also in Mississippi and other states. The trials provide an objective evaluation of private and public varieties under typical growing conditions at multiple locations.
Prior to the recent release of the 2000 variety trials in Arkansas, the overall three-year average yield of Caviness for 1997-1999 was 54.8 bushels per acre in irrigated and non-irrigated tests at all locations. The best three-year average was at Marianna, where Caviness averaged 60.5 bushels per acre. Its highest yield in 1999 was 65.2 bushels per acre at Stuttgart.
In Mississippi, the average yield of Caviness for 1997-1999 in both irrigated and non-irrigated tests at all locations was 44 bushels per acre. The highest yield in Mississippi was 70.4 bushels per acre at Stoneville in 1999.
Terry Fuller, chairman of the Caviness marketing group and owner of Fuller Seed and Supply in Poplar Grove, said Caviness seed will be priced below private brands but somewhat higher than other public varieties.
“Allowing farmers to save seed for planting on land they farm and blue tag certification by the State Plant Board are big advantages compared to private varieties,” he said.
“It's a mid-maturity Group V with a good range of performance at different planting dates, including late planting,” Ashlock added.
The variety is named for University Professor Emeritus Charles Caviness. He retired in 1991 after 30 years as leader of the U of A soybean breeding team that produced nine widely grown varieties. “Caviness” was selected from a breeding line that promises to produce more high-yielding varieties over the next few years.
Public varieties developed by plant breeding teams at land-grant universities and the USDA provided the genetic foundation for Arkansas' soybean industry. Legislation in the 1970s and 80s allowed private companies to, in effect, patent crop varieties. This led to private investment in major crop breeding programs. Public soybean varieties now compete with dozens of private brand-name varieties adapted to Arkansas conditions.
“Ag Genetics will help attract the attention that we think Caviness and future high-yielding varieties from the U of A and other public breeding programs deserve,” Weidemann said.
The new Caviness Soybean variety was unveiled to attendees of the recent Little Rock Farm Show where dealers exhibited information and provided literature and statistical information regarding physical characteristics, disease ratings, and average yields. One winner each day received 50 free units of Caviness soybeans. Congratulations go to Mart Thaxton of Ricky Branch Farms, Carlisle, Arkansas and Millard Branum of Trumann, Arkansas.
Fifty units of Caviness soybeans will also be given away each day at the Mid-South Farm and Gin Show in Memphis. Visit their booth number 5018 to register.
ABOUT THE COMPANY…ENGINES INC.
Engines, Inc., is headquartered in Weiner, Arkansas, approximately 70 miles west of Memphis and 100 miles northeast of Little Rock. In the last two decades we have grown to become the leading provider of diesel irrigation power units in the Mid-South; in addition, our generator set, Original Equipment Manufacturer (OEM), re-power and marine businesses have grown in response to the quality of our products and after-sale service.
Our flexible and open-minded approach to finding solutions has made us a favorite among farmers, businesses and manufacturers who appreciate the value we add to their operations with our reputation for quick and sensitive response and delivery.
As technology, regulations and lifestyle issues continue to reshape our markets and redefine the nature of our business, we remain focused on meeting changing needs with new and better products. At Engines, Inc., we treat the needs brought on by change as an opportunity rather than a problem. The amount of time between new product conception and prototyping is critical; moreover, this is where Engines, Inc., operates without peer. Our engineers work closely with our OEM engineers, outside vendors as well as our production staff. Computer-aided-design driven by experienced and dedicated craftsmen help us bring high quality, marketable solutions to the market place at record pace.
ABOUT OUR MARKET…
We have built our generation-long reputation on serving the needs of a wide variety of consumers who demand high quality, dependable power sources to meet their day-to-day needs.
Farmers who need reliable power units to drive their irrigation systems. Manufacturer's of engine-powered equipment whose reputations are tied to the quality of engines they use.
Manufacturer's of engine-powered marine equipment who have special needs for engines that can perform reliably in water-based environments.
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Our complete lines of high-quality diesel, gasoline and LP powered engines can be divided into five broad categories:
- Irrigation Power Units
- Generator Sets
- Original Equipment Manufacturer (OEM)
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