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Article Excerpt
Chair: Evelin J. Cuadra, Alcorn State University
Vice-chair: Gregorio B. Begonia, Jackson State University
FRIDAY MORNING
Hunter Henry Ballroom B
8:15 ENHANCING SUSTAINABLE PRODUCTION OF MEDICINAL PLANTS IN MISSISSIPPI
Patrick Igbokwe*, Liang Huam, Franklin Chukwuma, and Magid Dagher, Alcorn State University, Alcorn State, MS 39096
Field studies were used to determine the effect of 3 cropping systems and 3 row preparations on purple coneflower (Echinacea purpurea) survival, growth, yield and quality. The study was conducted on a Memphis silt loam soil in southwest Mississippi. A split plot arrangement in a randomized complete block experiment design was used for this study. The 3 cropping systems made up the main-plot, whereas the 3 row preparations made up the sub-plot. Each of the 3 row preparations was replicated 4 times. Cropping systems influenced plant survival, canopy height, root dry weight and root volatile soil during both 2004 and 2005 study periods. Row preparations also influenced plant survival, canopy height and root volatile oil during the same period.
8:30 REOCCURRENCE OF ANGULAR LEAF SPOT OF COTTON IN MISSISSIPPI AND EVALUATION OF CURRENTLY GROWN VARIETIES FOR IMMUNITY OR RESISTANCE TO THE DISEASE.
G. L. Sciumbato*, P. S. Thaxton, and Jim Nichols, Delta Research and Extension Center, Mississippi State University, Stoneville, MS 38776
Angular leaf spot or bacterial blight was a major disease of cotton (Gosspyium hursitum) in Mississippi prior to the use of acid delinted cotton. The bacterium is mostly transmitted on the surface of the seed and the acid delinting process eliminated the bacterium. There was also genetic resistance to the disease. However, the major source of resistance was Tamcot SP-37 and varieties with a SP-37 background were very susceptible to bronze wilt and were discontinued. In addition, environmental concerns about acid delinting have resulted in newer methods of removing the lint from cotton which do not use acid. These new methods allow the bacterium to survive the delinting process. The bacterium has been isolated by us from several locations in Mississippi in recent years. The race of the bacterium is primarily race 18 and not a new race. We have screened 52 varieties for resistance to the disease using a high pressure sprayer in field plots. Thirteen varieties were immune and eleven varieties had a high degree of resistance to the disease. The other twenty-three varieties were susceptible to very susceptible.
8:45 EVALUATION OF DIFLUBENZURON (DIMLIN[R]) TO CONTROL CERCOSPORA SOJINA, THE FROGEYE LEAFSPOT PATHOGEN OF SOYBEAN
C. Wells (1,2*), R.E. Baird (1), and G. L. Sciumbato (2), (1) Mississippi State University, Mississippi State, MS 39762 and (2) Delta Research and Extension Center, Stoneville, MS 38776
Diflubenzuron, a benzamine chitin-inhibitor commonly used as an insecticide, has been reported to have fungicidal activity in Mississippi against, Cercospora sojina, the frogeye leaf spot (fls) pathogen of soybean. Chemical applications for control of both insects and fls would result in reduced costs for soybean producers and less potentially harmful chemicals in the environment. To further investigate diflubenzuron's fungicidal activity, two field trials were established during the 2006 growing season in two locations in Mississippi. Within each trial, one determinate and one indeterminate variety were planted in a randomized complete block design with four replications per treatment. Four treatments consisting of diflubenzuron (2.0 and 4.0 oz/[R]), pyraclostrobin (Headline[R])(4.7 oz/A) and an untreated control were repeated, one set was artificially inoculated with C. sojina and one set using natural inoculum. Within the artificially inoculated plots, one set received inoculum 24 h prior to and one 24 h after chemical treatments. Disease ratings were performed two and four weeks after inoculation. Yield data were also recorded. The excessively dry environmental conditions in 2006 were unfavorable for disease development. Therefore, no significant differences in disease ratings or yield were seen between the eight treatments according to the Waller-Duncan K ratio [t.bar] Test at the P<0.05 level. Field trials will be repeated in 2007.
9:00 IDENTIFYING ISOLATES OF PHYTOPHTHORA CINNAMOMI FOR CHALLENGING BLUEBERRY (VACCINIUM sp.) CULTIVARS TO DEVELOP A GREENHOUSE SCREENING TECHNIQUE FOR IDENTIFYING RESISTANT BLUEBERRY GERMPLASM
Melinda Miller-Butler (1*), Kenneth J. Curry (1), and Barbara J. Smith (2), (1) University of Southern Mississippi, Hattiesburg, MS 39406 and (2) USDA-ARS Southern Horticultural Laboratory, Poplarville, MS 39470
The production of blueberries (Vaccinium sp.) in Mississippi, occupies over 2000 acres as of 2006. Phytophthora cinnamomi causes severe root rot on many woody plant species including blueberries. Soil samples were collected from symptomatic blueberry plants at several farms in Mississippi. Successful isolations were made using a floating leaf technique and placing the leaf pieces on media amended with antibiotics and fungicides. Unidentified isolates were confirmed with a Phytophthora-genus specific ELISA test. Known isolates of Phytophthora cinnamomi were obtained from an outside source. Seedlings with little or no resistance to phytophthora root rot were challenged with all isolates. Unidentified isolates causing premature senescence in the seedlings will be used to challenge young blueberry plants for developing a greenhouse technique to identify blueberry germplasm resistant or at least tolerant to phytophthora root rot. Ultimately this will lead to the development of resistant cultivars that offer a means of controlling this disease in commercial blueberry fields.
9:15 ESTABLISHMENT OF BLACKBERRIES AND DETECTION AND MANAGEMENT OF RASPBERRY CROWN BORER
Edward Heard, Frank Matta*, Blair Sampson, John Braswell, and Juan Silva, Mississippi State University, Mississippi State, MS 39762
Field evaluations of new tactics for early detection and management of raspberry crown borer, RCB, Pennisettia marginata (Harris) (Lepidoptera: Sesiidae) on blackberries, Rubus L. subgenus Rubus Watson, were performed at the Mississippi Agriculture and Forestry Experiment Station North Farm from December 2004 to July 2006. RCB is the primary limiting factor for blackberry production in Mississippi. Borer damage to canes and crowns underground can increase and go undetected until a crop is devastated by infestation. A randomized field plot with 3 adjacent rows was planted with infested blackberries and certified nursery stock of two recommended cultivars, thorny 'Chickasaw' and thornless 'Apache'. Insect pest management tactics targeting RCB included the following soil drenches: chemical insecticide bifenthrin, recently registered and labeled for RCB management; experimental pesticide E2Y45, being evaluated in association with USDA IR-4 Program; entomopathogenic nematodes Steinernema feltiae, beneficial organisms effective against several species of clearwing-borer moths including limited success against RCB. Before application of S. feltiae, unknown effects of pesticides on nematode viability and infectivity were evaluated in laboratory bioassays with late instar host greater wax moth larvae, Galleria mellonella (L.). Pesticides evaluated include the fungicides captan, pyraclostrobin + boscalid, lime-sulfur and the insecticide acetamiprid. Bioassays tested two entomopathogenic nematode species, S. feltiae and Heterorhabditis bacteriophora. Results indicated that lime-sulfur severely limited nematode movement and infectivity at 100% and 10% application rate. Pyraclostrobin + boscalid decreased movement of both nematode species and infectivity of S. feltiae at 100% and 10% rate. Lower rates are not significant. Methods for early detection of RCB include placement of sticky traps baited with variable amounts of insect pheromones (E,Z)313-octadecadien-1-ol and/or (E,Z)3-13-octadecadien-1-yl acetate at 4 sites within the plot.
9:30 BIOAVAILABILITY OF MERCERY IN SOIL AND WATER AND ITS EFFECTS ON PLANT STRUCTURE AND REFLECTANCE
Safwan Shiyab, Frank Matta*, F. X. Han, Yi Su, and D.L. Monts, Mississippi State University, Mississippi State, MS 39762
There is great concern regarding the clean up of toxic pollutants from the environment. Phytoremidiation is a process, environmentally friendly, and cost-effective to clean up heavy metals and the other toxic compounds from contaminated environments. Mercury contamination is ubiquitous in the Y-12 watershed of Oak Ridge, TN and has been identified as a key contaminate in soil, sediment, surface water, and ground water....
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