Spider mite webbing. Part IV: The effect of acaricides on spinning by the carmine spider mite Tetranychus cinnabarinus (boisduval)

Cyhexatin, dienochlor and four experimental acaricides, U-25322 (1-benzoyl-3-phenylhydrazine), U-27415 1-benzoyl-3-(2, 4, 6-trichlorophenyl)hydrazine, U-42558 [N¹(4-chloro-o-tolyl) N²-methyl-N¹-(phenylthio)formamidine], and U-42564 [N²-methyl-N¹-(phenylthio)- N¹-(2, 4-xylyl)formamidine], at 125 mg litre-¹, induced spindown by the carmine spider mite, Tetranychus cinnabarinus (Boisduval). Cyhexatin caused the largest number of mites to spin-down, dienochlor the least. Spinning occurred only during the first 6 h after treatment. Mites spun the same average length of threads in response to all compounds. The pattern of spin-down was even and similar for all the compounds except dienochlor for which it was sporadic. Acaricide-induced spin-down is postulated to be an ‘all-or-nothing’ reaction.     

RADIOGRAPHIC CHANGES IN TESTES OF BULLS INFECTED WITH BESNOITIOSIS

Ten beef bulls infected with Besnoitiosis were examined radiographically and pathologically. Eight of these were slaughtered soon after diagnosis; two were left for a six-month observation period. The radiographic findings were focal and branching-tree calcification of the testes. Histopathologic examination proved these calcifications to be necrotic sections of the seminiferous tubules. Radiography of the testes as a means of evaluating the fertility status of the infected bull is recommended.     

Development of crown and root rot disease of tomato under irrigation with saline water

ABSTRACT We studied the effect of water salinity on the incidence and severity of crown and root rot disease of tomato, as well as on the pathogen and on the plant's response to the pathogen. Irrigation with saline water significantly increased disease severity in tomato transplants inoculated with Fusarium oxysporum f. sp. radicis-lycopersici, and mineral fertilization further increased it. In one field experiment, disease incidence in plots irrigated with saline water (electrical conductivity [EC] = 3.2 +/- 0.1 dS m(-1)) and in those irrigated with fresh water (EC = 0.4 +/- 0.1 dS m(-1)) was 75 and 38%, respectively. Disease onset was earlier and yield was lower in plots irrigated with saline water. In a second field experiment, final disease incidence 250 days after planting, was 12% in plants which had been irrigated with saline water (EC = 4.6 +/- 0.1 dS m(-1)) and 4% in those irrigated with fresh water (EC = 1.2 +/- 0.1 dS m(-1)). Irrigation of tomato transplants with 20 mM NaCl did not inhibit plant development, but partial inhibition was observed at higher NaCl concentrations. Growth of the pathogen in culture or survival of conidia added to soil were not affected by saline water. Plants which were preirrigated with saline water were more severely diseased than those preirrigated with tap water. It was concluded that disease increases effected by saline water are associated with the latter's effect on plant response.     

MULTIPLE CONGENITAL URINARY TRACT ABNORMALITIES IN A BITCH: A CASE HISTORY REPORT

A 2 1/2-month-old, female German Shepherd Dog was examined because of incontinence since birth. Multiple urinary anomalies which included left renal agenesis, right hydronephrosis and hydroureter and urinary bladder dysfunction were found by excretory urography. These abnormalities were confirmed at necropsy. In addition, vesicovaginal continuity with apparent absence of the urethra was also found     

The effect of potassium on yield,nutrient uptake and efficiency of teff (Eragrostis tef Zucc. Trotter) on vertisols of North Western Ethiopian Highlands

Vertisols are characterized by deficiency of nutrients and recently, potassium (K), a major plant nutrient in crops, is gaining attention because of crop removal, fixation by clay minerals and leaching. A field experiment was conducted during the 2015 and 2016 main cropping seasons to test the effect of potash fertilizer on Vertisols of East Gojjam at Gudalima and Dejen/Tik sites using teff crop. The K rates (applied as muriate of potash) were 0, 50,100, and 150?kg ha^?1. The experiment was laid out in a randomized complete block design in three replications. The results indicated that the plant height, panicle length, number of effective tillers, dry matter and grain yield of teff increased significantly (P?<?0.05) with applied K. The highest dry matter and grain yield (6966.4 and 2418.2 kg ha^?1, respectively) were obtained from the application of 100 kg ha^?1 KCl. Total uptake of N, P, and K were enhanced significantly with K treated plots than those without and K efficiency was improved due to the rate of K. The present study demonstrated the importance of K application to supplement NPS for optimum dry matter and grain yield of teff on Vertisols of the study sites.     

Numerical investigation of irrigation scheduling based on soil water status

Improving the sustainability of irrigation systems requires the optimization of operational parameters such as irrigation threshold and irrigation amount. Numerical modeling is a fast and accurate means to optimize such operational parameters. However, little work has been carried out to investigate the relationship between irrigation scheduling, irrigation threshold, and irrigation amount. Herein, we compare the results of HYDRUS 2D/3D simulations with experimental data from triggered drip irrigation, and optimize operational parameters. Two field experiments were conducted, one on loamy sand soil and one on sandy loam soil, to evaluate the overall effects of different potential transpiration rates and irrigation management strategies, on the triggered irrigation system. In both experiments, irrigation was controlled by a closed loop irrigation system linked to tensiometers. Collected experimental data were analyzed and compared with HYDRUS 2D/3D simulations. A system-dependant boundary condition, which initiates irrigation whenever the matric head at a predetermined location drops below a certain threshold, was implemented into the code. The experimental model was used to evaluate collected experimental data, and then to optimize the operational parameters for two hypothetical soils. The results show that HYDRUS 2D/3D predictions of irrigation events and matric heads are in good agreement with experimental data, and that the code can be used to optimize irrigation thresholds and water amounts applied in an irrigation episode to increase the efficiency of water use.     

Survey of Pesticide Distribution in Upper Jordan Basin

A survey was conducted of pesticide distribution in the water ofthe upper Jordan basin, due to the importance of its quality asthe main source of drinking water in Israel.A preliminary survey of pesticide distributers and farmersrevealed intensive use of many pesticides in agriculture. Fourof these were selected as targets for monitoring in the surfacewater of the region, at seven sampling stations. The highestresidue found was of aldicarb and its metabolites, with lowercontent of organophosphate and organochlorine insecticides. Noconcentrations reached the maximum levels permitted by the EPAfor drinking water, but recommendations were made, nonetheless,for continuous monitoring of pesticides in the region.Subsequent monitoring (1993–1997) showed a steady decrease in aldicarb residues.