Use of Fungicides and Biological Controls in the Suppression of Fusarium Crown and Root Rot of Asparagus Under Greenhouse and Growth Chamber Conditions.

Growth chamber, greenhouse, and field experiments were conducted with fungicides and biological control agents, including nonpathogenic isolates of Fusarium oxysporum, to test their ability to control disease caused by F. oxysporum f. sp. asparagi and F. proliferatum. In greenhouse studies with asparagus seedlings in soil, Trichoderma harzianum strain T-22, benomyl, and fludioxonil treatments increased root weight and decreased root disease compared with the infested control when a low level of F. oxysporum f. sp. asparagi and F. proliferatum was used. The fungicide fludioxonil limited plant death caused by Fusarium spp. at high inoculum levels, whereas T. harzianum strain T-22 was not effective. Nonpathogenic isolates of F. oxysporum were effective in limiting Fusarium disease on asparagus seedlings in culture tubes, although isolates differed in their ability to control disease caused by F. oxysporum f. sp. asparagi and F. proliferatum. In greenhouse studies, no significant differences in plant death were found between asparagus plants growing in media infested with F. oxysporum f. sp. asparagi and F. proliferatum and left untreated, and those treated with nonpathogenic F. oxysporum. The efficacy of fungicides and biological control products to control Fusarium crown and root rot under commercial field conditions could not be evaluated due to low disease pressure.

Effects of Sodium Chloride on Commercial Asparagus and of Alternative Forms of Chloride Salt on Fusarium Crown and Root Rot.

Experiments with applications of NaCl (560 and 1,120 kg/ha) and lime (6,719 kg/ha) were conducted in asparagus fields in commercial production (one healthy and one exhibiting symptoms of early decline), and an experiment with NaCl (1,120 kg/ha) was conducted in a badly declined research field at Michigan State University from 1998 to 2000 to determine whether these treatments control Fusarium crown and root rot of asparagus. Growth chamber and greenhouse studies were conducted to test the ability of alternative forms (CaCl2, NH4Cl, and MnCl2) of chloride salt to reduce disease caused by F. oxysporum f. sp. asparagi and F. proliferatum. NaCl applications increased yield and fern health in the research plot, but not in commercial fields. Soil tests in these fields indicated that NaCl did not decrease levels of calcium, magnesium, or potassium, and did not affect pH. In growth chamber studies with asparagus seedlings in Hoagland's agar test tubes, and in greenhouse studies with asparagus seedlings in soil, none of the alternative forms of chloride salt tested were more effective than NaCl in controlling Fusarium crown and root rot.

Artificial induction of red gut in sheep.

Eight out of 10 lambs died within six to 11 hours after occlusion of the cranial mesenteric blood vessels by a snare placed around both the artery and vein. Death resulted from shock and was accompanied by post mortem findings identical to those seen in red gut. It is suggested that the cause of death in the naturally occurring disease is from arrested mesenteric blood flow following intestinal torsion.

A survey of nematode control measures used by milking goat farmers and of anthelmintic resistance on their farms.

Forty-seven milking goat herds, located throughout New Zealand, were surveyed for anthelmintic usage and for gastrointestinal nematodes resistant to anthelmintics. Most farmers (62%) followed a predetermined drenching programme and usually (68%) had a policy of alternating between drench families. Alternation was generally within the farming year. Kids were on average being drenched 12.5 times during their first year (range 2-34). Does aged greater than one year were all being drenched at the same frequency (average 13.4, range 2-34) irrespective of age. On each of the 47 farms, a group of goats was treated with a benzimidazole (BZ) drench (oxfendazole, OFZ, at 4.5 mg/kg on 36 farms and thiabendazole, TBZ at 66 mg/kg on 11 farms); a second group was treated with a "cell membrane depolarizing" (CMD) drench (levamisole, LEV, at 8 mg/kg on 35 farms and morantel citrate, MOR, at 10 mg/kg on 12 farms); a third group remained untreated as controls. Faecal egg counts and larval cultures were done before dosing and one week later. Faecal egg count depressions of <80% were taken as being suggestive of anthelmintic resistance. On this basis resistance was found on 79% of farms surveyed. Resistance to BZs alone occurred on 36% of farms, resistance to CMDs alone on 4% and resistance to both on 38% of farms. On 23% of farms one or other of the drenches was without any apparent effect and on one farm both of the drenches tested failed to reduce the egg counts. Post-drenching larval cultures showed Trichostrongylus, Haemonchus and Ostertagia to be the most prevalent genera remaining after drenching with BZ on 14,11, and 8 farms, respectively. After drenching with LEV Ostertagia was the dominant species on 10 farms, Trichostrongylus on 2 and on one farm the two genera were equally common. Following treatment with MOR Trichostrongylus was the dominant species on 3 farms, Haemonchus on 2 and on one farm Trichostrongylus and Ostertagia were equally common. There was a positive association between drenching frequency and the presence of resistance on farms. Possible interpretations of this association are discussed.

Liver copper concentrations in red deer (Cervus elaphus) and wapiti (C canadensis) in New Zealand.

Concentrations of copper in livers from red deer (Cervus elaphus) or wapiti (C canadensis) were measured and classified according to the age and species of the animals whether farmed or feral, the area from which they came and their sex. Significant variations occurred with age, species, environment (farmed or feral) and area. Mean liver copper concentrations (after logarithmic transformation) ranged from 356 mg/kg of fresh matter in fetus/neonate to 10.5 mg/kg in mature animals.

Simple medium for the selective isolation of Bacteroides and related organisms, and their occurrence in sewage.

A medium composed of 0.009% sodium azide, 0.07% sodium deoxycholate, and 0.0007% ethyl violet in Brain Heart Infusion Agar (Difco) and a process of incubation in an atmosphere of 90% N(2) and 10% CO(2) for the selective isolation of certain members of the intestinal bacteroides are described. The medium appears to select predominantly members of the genus Bacteroides and a few of the genus Sphaerophorus. A survey of the occurrence of these organisms in sewage and various stages of sewage treatment indicates that they survive complete sewage treatment in low numbers and that their rate of decline parallels that of the coliforms. Large numbers were recovered from sludge digestion tanks, suggesting a possible role in the anaerobic breakdown of organic matter.