Glufosinate and ammonium sulfate inhibit atrazine degradation in adapted soils

The co-application of glufosinate with nitrogen fertilizers may alter atrazine cometabolism, thereby extending the herbicide’s residual weed control in adapted soils. The objective of this study was to assess the effects of glufosinate, ammonium sulfate, and the combination of glufosinate and ammonium sulfate on atrazine mineralization in a Dundee silt loam exhibiting enhanced atrazine degradation. Application of glufosinate at rates of 10 to 40 mg kg⁻¹ soil extended the lag phase 1 to 2 days and reduced the maximum degradation rate by 15% to 30%. However, cumulative atrazine mineralization averaged 85% 21 days after treatment and was independent of treatment. Maximum daily rates of atrazine mineralization were reduced from 41% to 55% by application of 1 to 8 g kg⁻¹ of ammonium sulfate. Similarly, cumulative atrazine mineralization was inversely correlated with ammonium sulfate rates ranging from 1.0 to 8 g kg⁻¹ soil. Under the conditions of this laboratory study, atrazine degradation was relatively insensitive to exogenous mineral nitrogen, in that 8 g (NH₄)₂SO₄ per kilogram soil repressed but did not completely inhibit atrazine mineralization. Moreover, an additive effect on reducing atrazine mineralization was observed when glufosinate was co-applied with ammonium sulfate. In addition, ammonium fertilization alters the partitioning of ¹⁴C-atrazine metabolite accumulation and nonextractable residues, indicating that ammonium represses cleavage of the triazine ring. Consequently, results indicate that the co-application of glufosinate with N may increase atrazine persistence under field conditions thereby extending atrazine residual weed control in adapted soils.     

Gross Morphology of Diseased Tissues in Nezara viridula (Hemiptera: Pentatomidae) and Molecular Characterization of an Associated Microsporidian

Nezara viridula (L.) (Hemiptera: Pentatomidae), commonly known in the U.S. as the southern green stink bug (SGSB), is a cosmopolitan, highly polyphagous feeder that causes severe damage to a wide range of agronomically important crops such as fruit, vegetable, grain, tobacco, and cotton, throughout much of the United States, and is a global pest of considerable ecological, agricultural, and economical interest. During dissection of female Nz. viridula, conspicuous black and brown spots or lesions were observed on various internal organs. To determine the cause of these spots or lesions, tissues of fat body, spermatheca, ovaries, and ovulated eggs were collected from healthy and infected individuals. The gross morphology of the spots was characterized, and the microorganisms associated with the infection were identified by amplicon sequencing of the V4 region of the small subunit rRNA gene. The presence of a microsporidian pathogen Nosema maddoxi, Becnel, Solter, Hajek, Huang, Sanscrainte, & Estep (Microsporidia: Nosematidae) which has been observed on other species of stink bug, was evidenced for the first time. The characterization of the gross morphology of this associated microsporidian may enable more rapid determination of microsporidia infection in stink bug colonies and field populations.     

An epidemiological survey of the feline urological syndrome

An epidemiological survey of the feline urological (or urolithiasis) syndrome (FUS) was carried out from 1 October 1973 to 30 September 1974. Details of 437 FUS cases were recorded by veterinary surgeons in thirty-three practices. An independent market research organisation collected corresponding details, where applicable, of 604 pet cats selected randomly from the pet cat population of the practice areas.
Total incidence of reported cases was estimated at about 0.64% of the domestic cat population in one year. The number of cases of FUS was highest in the autumn and winter of 1973 and then decreased to the end of the survey period.
Comparison of clinical and control surveys showed an association of the disease with several factors. These included age, diet and neutering (especially of male animals). By comparison with the controls, FUS cats tended to drink less, to be fed on dry cat food, to be considered lazy, taking little exercise, to have less freedom to leave the house at will and to be provided with indoor urinating facilities. There was also some evidence of an association with the brand of dry cat food and with the number of cats in the household. These factors were not necessarily either causative agents or additive in effect. A follow-up survey revealed a FUS mortality of 22% (90/403 cats) at 6 months after the survey episode, the majority dying or being put down in the first week. The death-rate was higher in males. Further episodes were noted in 32% of the cats followed up. The rate of recurrence was the same in those cats (68%) whose diet had been changed after the initial episode.     

Effect of zearalenone on the fertility of virgin dairy heifers

Eighteen cycling, virgin, Holstein heifers daily were given 250 mg of 99% purified zearalenone in a gelatin capsule orally, and 18 controls were given an empty gelatin capsule once a day. The study lasted through 1 non-breeding estrous cycle and the next 2 consecutive estrous cycles during which the 36 heifers were bred, using artificial insemination. Serum concentrations of progesterone and complete blood cell counts were determined throughout the study. The treated and control heifers had conception rates of 62% and 87%, respectively. There was no effect (P less than 0.05) on the serum concentration of progesterone or the complete blood cell counts. Three heifers, bred but not pregnant by the end of the study, were euthanatized and necropsied. The treated heifer did not have any zearalenone-attributable lesions, and there was no effect seen in the bone marrow smears. The remaining 33 heifers were sold as a herd, and the 31 pregnant heifers calved normally. There was no effect (P less than 0.05) on the sex ratio of the offspring, which were all clinically healthy. Zearalenone did lower the conception rate of the treated heifers (P less than 0.065).     

Survey with follow-up of 67 dogs with testicular sertoli cell tumours

Sixty-seven cases of canine sertoli cell tumour are reviewed. The mean age at diagnosis was 9.5 years (sd +/- 2.1, range 3 to 17). The most commonly affected breeds were boxer, cairn terrier, labrador retriever, border collie, German shepherd and rough collie. The left side was affected in 28 dogs (42 per cent), the right in 35 (52.5 per cent) and both sides in four (6 per cent). Twenty testicles were abdominal (left, seven; right, 13), seven were inguinal (left, four; right, three) and 44 were scrotal (left, 21; right, 23). Hormonal signs were evident in 38 (57 per cent) animals (feminisation with alopecia in 21, symmetrical alopecia alone in 17). Other types of testicular tumours were found in 12 dogs (18 per cent) of this series. Of 42 dogs which were castrated and discharged, 38 were available for follow-up study and survived for between one week and five years. Two of the 15 dogs which were subject to post mortem examination had metastases. Two others which died after failure of remission, or a recurrence of the hormonal changes probably also had metastases. Two of the 25 dogs which were presented initially for other reasons, but had sertoli cell tumours, were found to have metastases post mortem. The boxer, cairn terrier, border collie, Shetland collie and pekingese had a higher risk of sertoli cell tumour than other breeds.