The Impact of Plant Essential Oils and Fine Mesh Row Covers on Flea Beetle (Chrysomelidae) Management in Brassicaceous Greens Production

Brassicaceous leafy greens are an important crop for small growers but are difficult to produce due to damage by flea beetles. Flea beetles are problematic for growers as they chew many small holes through leaves rendering produce unmarketable. We tested the efficacy of several essential oils, the woven-mesh row cover ProtekNet, and the spunbonded row cover Agribon, compared to organic and conventional insecticides and no spray controls in the spring and fall of 2019. We found that the two row cover treatments (Agribon and ProtekNet) provided the best control of flea beetles and associated damage. Thyme oil was highly phytotoxic and killed the crop entirely and rosemary and neem essential oils caused mild phytotoxic burns. Organic insecticides rarely performed better than the no spray control. While conventional insecticides controlled most flea beetles, the crop was often still too highly damaged to sell. The results of our study suggest row covers offer producers an effective method of flea beetle control that reduces their dependence on insecticides for conventional and organic production.

Bacterial Wilt of Cucurbits: Resurrecting a Classic Pathosystem

Bacterial wilt threatens cucurbit crop production in the Midwestern and Northeastern United States. The pathogen, Erwinia tracheiphila, is a xylem-limited bacterium that affects most commercially important cucurbit species, including muskmelon, cucumber, and squash. Bacterial wilt is transmitted and overwintered by striped and spotted cucumber beetles. Since there are few commercially available resistant cultivars, disease management usually relies on use of insecticides to suppress vector populations. Although bacterial wilt was initially described more than 100 years ago, our knowledge of disease ecology and epidemiology advanced slowly for most of the 20th century. However, a recent wave of research has begun to fill in missing pieces of the bacterial wilt puzzle. This article-the first review of research toward understanding the cucurbit bacterial wilt pathosystem-recounts early findings and updates our understanding of the disease cycle, including pathogen and vector biology. We also highlight research areas that could lead to more efficient and ecologically based management of bacterial wilt.

[Prevalence of tuberculosis and brucellosis in intra-urban and peri-urban dairy cattle farms in Ouagadougou, Burkina Faso]

A study of the prevalence of bovine tuberculosis and brucellosis was conducted in dairy cattle farms in and around the city of Ouagadougou, Burkina Faso. It reveals the potential economic and health impact of these two major zoonoses in the study area. Three farming systems were included in the study. A total of 1,420 cattle were tested for tuberculosis and 1,689 cattle were tested for brucellosis. The intradermal tuberculin test was used for tuberculosis, and the buffered antigen test and indirect enzyme-linked immunosorbent assay were used for brucellosis. The overall prevalence rate is estimated to be 6.05% for tuberculosis and 3.61% for brucellosis. The prevalence rates of tuberculosis and brucellosis in urban and peri-urban dairy cattle farms in Ouagadougou were found to be high. As these two production-linked diseases are zoonotic, they could pose a major risk to human health and contribute significantly to reducing animal production and productivity in the areas covered by the study. Animals should be checked systematically prior to introducing them into dairy herds, with the ultimate goal of eradicating these two zoonoses.

[Links between non-professional agents and the official Veterinary Services in sub-Saharan Africa]

Para-professional agents known as auxiliaries, or community animal health workers, provide low-cost basic veterinary services to communities of livestock producers. A 2003 survey of 16 Sub-Saharan African countries, carried out as part of the Pan-African Programme for the Control of Epizootics, showed that in the majority of cases, the official Veterinary Services have no (or very few) links with the auxiliaries, although they are well aware of their existence and in some cases the auxiliaries have been trained by officials of the Veterinary Services. However, there are isolated cases of countries establishing more formal links, for example, recognising the status of an auxiliary, recognising auxiliaries with no definition of a status, attaching auxiliaries to Veterinary Service staff, establishing agreements for the provision of auxiliary services through livestock producer associations, harmonising auxiliary training programmes, issuing professional auxiliary cards, and setting up a consultation framework on the issue of auxiliaries. Unlike private veterinarians, agents of the official services do not generally perceive auxiliaries as competitors, and sometimes collaboration develops at this level. The authors propose several measures to improve links between the official Veterinary Services and auxiliaries, as follows: the fields of competence of auxiliaries should be defined and their curriculum harmonised, the status of auxiliaries should be recognised, a monitoring and assessment mechanism should be established at senior level in the Veterinary Services, training for livestock producers should be improved.

[Larval Clinostomum infection of cichlid fish in the lake of Kompienga in Burkina Faso: a menace to haleutic exploitation and public health]

Clinostomum sp. is a trematode, a parasitic worm, of which the larva infest a number of species of wild fish. In intertropical Africa and particularly in artificial lakes in the east of Burkina Faso, the infestation is especially observed in the cichlids fish. Because cichlids constitute 80 to 90% of the fish catches, enzootic infestation could infringe upon the fisheries, and also adversely affect public health. For this epidemiological study conducted during the first three quarters of 1994, we examined a total of 932 cichlids, a mix of all species. Prevalence (Pr) and intensity (I, number of parasites per fish) were the two indicators of the infestation level. 387 fish were carriers of the parasite, comprising 41.5% of the total. Differences were observed between the species of cichlids. Oreochromis niloticus was the most infested (Pr, 56%; I, 17), followed by Sarotherodon galilaeus (Pr, 44%; I,6); and Hemichromis fasciatus (Pr, 20%; I, 5). In 89% of the carriers, the parasite was localized on the internal face of the operculum and in the pericardial septum, compared to 11% of the localizations in subcutaneous and muscular tissues. These last two localizations render the fish repugnant, and can cause the fresh fish to be rejected. If the parasitized fish is not rejected and then insufficiently cooked, as occurs at public grills with multitudes of consumers, the living parasite can penetrate and stay in the upper digestive tract and constitute a threat for consumer health.(ABSTRACT TRUNCATED AT 250 WORDS)

Single-step technique for staining Anaplasma marginale in bovine blood smears

Three available differential stains, Camco-Quik, Diff-Quik, and Wright-Giesma were compared for detection of intraerythrocytic Anaplasma marginale in bovine blood smears. In samples where < 1% to more than 51% of the RBC were infected, statistical analysis of the data indicated no significant difference in the detection of A marginale with Camco-Quik or Diff-Quik stains. However, a significantly lower percentage of infected RBC were detected when blood smears were stained with the Wright-Giemsa stain, compared with the other 2 methods.

Insulin and glucose response following oral glucose administration in well-conditioned ponies

Twenty-three well-conditioned ponies were evaluated for insulin and glucose response following oral glucose administration (1 g/kg bodyweight [bwt] as a 20 per cent solution). Ponies were defined as normal if total insulin secretion (TIS) was less than 149 mu iu/ml h and the glucose concentration was below 11.1 +/- 0.11 mmol/litre (200 +/- 2 mg/dl) at all times following oral glucose administration. When glucose concentrations were maintained below 11.1 +/- 0.11 mmol/litre, the area under the glucose curve (TG) was less than 17.4 mmol/litre/h (314 mg/dl/h). The ponies were assigned to four groups based on insulin and glucose response: Group 1 (n = 7), normal; Group 2 (n = 5), high insulin, normal glucose; Group 3 (n = 8), high insulin, high glucose and Group 4 (n = 3), high glucose, normal insulin. This classification is an initial attempt to define normal insulin and glucose response in ponies. Additional data need to be accumulated to define further insulin resistance and diabetes in ponies.

Triglyceride, insulin, and cortisol responses of ponies to fasting and dexamethasone administration

Ponies were evaluated for their response to feed withholding and exogenous administration of corticosteroids (dexamethasone 0.04 mg/kg intramuscular [IM]) in an attempt to reproduce the hyperlipemia syndrome. Because insulin resistance has been associated with hyperlipemia, all ponies were initially evaluated for insulin response to an oral glucose load and normal dexamethasone suppression of serum cortisol. Four ponies were identified as hyperinsulinemic reflecting insulin resistance. All ponies had suppressed cortisol concentrations following dexamethasone administration. Feed withdrawal resulted in hypertriglyceridemia by 48 hours in all ponies. Very low density lipoprotein-triglyceride (VLDL) fraction was primarily elevated. The administration of dexamethasone failed to increase the degree of triglyceridemia. Although insulin resistance has been proposed as the likely cause of the hypertriglyceridemia in ponies, in this study four of eight ponies were considered to have normal insulin responses and yet still developed hypertriglyceridemia.