Correlations of Morphological, Anatomical, and Chemical Features of Grape Berries with Resistance to Botrytis cinerea

ABSTRACT Resistance of mature berries of grapevine cultivars and selections to postharvest infection by Botrytis cinerea was assessed. Little or no resistance existed in most popular table grape Vitis vinifera cultivars, except in moderately resistant 'Emperor' and 'Autumn Black'. Highly resistant grapes were V. rotundifolia, V. labrusca, or other complex hybrids. Morphological, anatomical, and chemical characteristics of 42 genetically diverse cultivars and selections with various levels of resistance to B. cinerea were examined to determine which features were associated with resistance. We quantified the (i) density of berries within a cluster; (ii) number of pores and lenticels on the berry surface; (iii) thickness and number of cell layers in the epidermis and external hypodermis; (iv) amount of cuticle and wax; (v) berry skin protein content; (vi) total phenolic content of the skin before and after B. cinerea inoculation; and (vii) catechin and trans- and cis-resveratrol contents of the skin before and after inoculation. The number of pores was negatively correlated with resistance. Highly resistant cultivars had few or no pores in the berry surface. The number and thickness of epidermal and hypodermal cell layers and cuticle and wax contents were positively correlated with resistance. Other characteristics evaluated were not associated with resistance. trans-Resveratrol and cis-resveratrol were induced by B. cinerea inoculation only in sensitive and moderately resistant cultivars and selections.     

Field evaluation of capsaicin as a rodent aversion agent for poultry feed

Developing additional techniques for reducing animal feed contamination by rodents and controlling rodent populations is critical to efforts aimed at reducing the occurrence of Salmonella spp infection on poultry farms. Capsaicin, a compound found in chili peppers of the genus Capsicum, produces a burning sensation in the mouth of mammals and is used effectively as an animal deterrent for some pest species. Applied to poultry feed, capsaicin may be effective as an aversive agent to deter rodent feeding and enhance acceptability of rodenticide baits. We tested capsaicin-treated poultry diets (2000 and 3000 Scoville Heat Units, SHU) in no-choice feeding trials at four active New York farms in the winter of 1997-1998. At all farms, consumption of the 2000 SHU diet by rodents (Norway rats, Rattus norvegicus (Berk), and house mice, Mus musculus L) was significantly less than consumption of a control diet. Consumption of the 3000 SHU diet by rodents was significantly less than consumption of a control diet at three of the four farms. Overall, consumption of treated diets was 58-97% and 55-98% less than consumption of the control diet, for the 2000 and 3000 SHU diets, respectively. These reductions appeared to be related closely to the availability of alternative feed sources at these farms. Two-choice feeding trials involving a rodenticide bait (0.05 g kg(-1) brodifacoum) and the 3000 SHU diet demonstrated that Norway rats preferred the rodenticide to the capsaicin-treated poultry feed. Overall, rodenticide bait acceptance was high (95.6%) when offered simultaneously with capsaicin-treated poultry feed. Although poultry managers must utilize several techniques to manage rodent pests, the use of capsaicin-treated diets to reduce feed losses and increase rodenticide bait acceptance appears promising. Use of capsaicin-treated feed on poultry farms may substantially reduce feed contamination by rodents and ultimately the incidence of Salmonella infection in poultry.     

Effect of sulfadiazine and pyrimethamine on selected physiologic and performance parameters in athletically conditioned thoroughbred horses during an incremental exercise stress test

Following the regimen used to treat equine protozoal myeloencephalitis, sulfadiazine (20 mg/kg) and pyrimethamine (1mg/kg) were administered orally once daily to 12 physically conditioned Thoroughbred horses for 4 consecutive days. The horses were randomly assigned to two test groups in a crossover design, with each horse serving as its own control. A stepwise exercise stress test was conducted to exhaustion. No effect on athletic performance was observed, and only marginal effects were noted in some hematologic and serochemical measurements, including decreased total white blood cell counts, red blood cell distribution width, total hemoglobin, serum sodium, and serum chloride. Serum folic acid concentration decreased significantly following sulfadiazine/pyrimethamine treatment.     

Effect of flunixin meglumine on selected physiologic and performance parameters of athletically conditioned thoroughbred horses subjected to an incremental exercise stress test

Twelve clinically sound, healthy, athletically conditioned Thoroughbred horses were subjected to an incremental exercise stress test to determine the effects and period of detection of a single dose of flunixin meglumine (1.1 mg/kg by intravenous injection) in serum and urine by ELISA. Flunixin concentrations, performance, and hematologic and clinical chemical parameters were measured. All horses were rotated through four treatment groups of a Latin-square design providing for each horse to serve as its own control. Flunixin meglumine reduced prostaglandin F(1alpha) and thromboxane concentrations that had been increased by intense exercise. Performance parameters did not improve and prostaglandin concentrations did not significantly correlate with total run time. Exercise did not change the flunixin elimination profile in either serum or urine, and concentrations were found to be below the detection limit of the ELISA test within 36 hours in serum and 120 hours in urine.     

Control of brown blotch of Bambara groundnut with garlic extract and benomyl

Field trials were conducted over two seasons to evaluate the efficacy of a water extract of garlic either alone, or in combination with reduced quantities of Benlate (benomyl 50% a.i., WP), for control of brown blotch of bambara groundnut caused byColletotrichum capsici. Results obtained showed that garlic extract has potential for control of brown blotch under field conditions, although it is not so effective as benomyl. Combining the extract with lower dosages of benomyl, however, appeared to have a synergistic effect. Consequently, the treatment comprising half the recommended dosage of benomyl (0.3 gl ⁻¹) combined with 1% (w/v) garlic extract was as effective as the full dosage of the fungicide which gave complete control of the disease. http://www.phytoparasitica.org posting Feb. 2, 2003.     

Selection for abamectin resistance in colorado potato beetle (coleoptera: Chrysomelidae)

There was no difference in dose response to abamectin between a laboratory strain of Colorado potato beetle (Leptinotarsa decemlineata (Say))from North Carolina and a multiple resistant strain from Massachusetts (LD₅₀= 1.95 and 1.98 ng larva^?1, respectively). Two abamectin-resistant strains were generated by separate means. The mutagen, ethyl methanesulfonate, was used to generate an abamectin-resistant strain (LD₅₀= 29.4 ng larva^?1) from the susceptible laboratory strain. The other resistant strain (LD₅₀ = 45.3 ng larva^?1) was generated through an intense selection with abamectin of a field strain contained in cages set up in existing potato fields. Resistance ratios calculated from LD₅₀values for the two abamectin-resistant strains were 15-fold and 23-fold, respectively. Resistance ratios calculated from LD₉₇values (21-fold and 38-fold, respectively) were higher than those calculated at LD₅₀. Also, there were larvae in both resistant strains which were capable of surviving doses up to 100 ng larva^?1, while the susceptible strain had no survivors at 10 ng larva^?1. Although the logit mortality regression analysis produced statistically different lines for the two abamectin-resistant strains, the slopes of each appear to be the same. Both resistance factors were determined to be autosomal and incompletely recessive (0.26 to 0.4, respectively) via reciprocal F₁crosses to the susceptible laboratory strain.     

The synthesis of pyrroles with insecticidal activity

The 2-aryl-4-bromo-5-trifluoromethylpyrrole-3-carbonitriles represent a new class of insect control agents. The high insectidical activity observed in this series prompted us to investigate the preparation of regioisomeric arylhalotrifluoromethylpyrrole carbonitriles. The synthesis and biological activity of eight of the twelve possible regioisomers are described and discussed.     

First report of southern blight of common barley in Puerto Rico

In 1990–91, 96% of the test plants in a barley (Hordeum vulgare L.) winter nursery in Puerto Rico was lost toSclerotium rolfsii. Small necrotic lesions (1–3 mm long) developed at the base of the stem, followed by wilting and general chlorosis as the lesions progressed and eventually girdled the base of the stem. Sclerotia then developed on the plants at the stem base. Two morphologically different strains ofS. rolfsii that were mycelial incompatible were isolated. This is the first report of a destructive blight due toS. rolfsii on field barley in the Caribbean. The apparent rate of disease increase (r) was estimated to be 12.2% per day using the logistic model, with an initial disease incidence of 0.042% (R²=0.89, p<-0.001).