A spray technique for mass release of eggs of Micromus tasmaniae Walker (neuroptera: Hemerobiidae)

Laboratory and glasshouse tests showed that eggs of Micromus tasmaniae Walker (Neuroptera: Hemerobiidae) can be sprayed at 206 kPa pressure with a specially developed compressed-air sprayer without impairing viability. The effects of five materials (agar, sucrose, gelatin, plant glue and xanthan gum) in water solution on egg hatching were tested and xanthan gum solution (0·03%) was selected as a suitable liquid medium for suspending the eggs and making them adhere to potato foliage. Egg losses during spraying may be greatly affected by wind drift, the amount of exposed soil (which is related to the stage of foliage development) and other environmental factors. The possibility of a spray technique for mass release of M. tasmaniae eggs in the biological control programme for potato pests is discussed.     

Effect of mating on rate of predation of two species of predacious mites,Agistemus exsertus Gonz. andPhytoseiulus persimilis Ath.-Hen.

The effect of successive matings on the rate of predation of two species of predacious mites,Agistemus exsertus Gonz. andPhytoseiulus persimilis Ath.-Hen., was investigated in the laboratory. With both species, multiple-mated and single-mated females exerted significantly a higher rate of predation on nymphs of the red spider mites during a shorter longevity duration compared to unmated females.With 2 figures and 2 tables     

Water-use efficiency of sorghum and groundnut under traditional and current irrigation in the Gezira scheme, Sudan

In the Gezira irrigation scheme in central Sudan, serious symptoms of water waste have been identified in the last two decades, especially in sorghum and groundnut fields. To quantify losses, water-use efficiencies and related parameters were obtained for these two food crops under the traditional attended daytime water application and the newly evolved unattended continuous watering method. In this on-farm research, the neutron scattering method was used to determine the actual soil water deficits of the two crops. A simple Penman equation was used for approximating reference crop evapotranspiration and evaporation losses from standing water and wet soil surface. An updated approach using the Penman-Monteith equation was additionally applied. The study revealed wastage of irrigation water in both irrigation methods but at different rates and also differently for each crop. In the attended field, the average seasonal over-irrigation, which is the difference between average application depth Q and average soil moisture deficit SWD, was observed to range between 0.4 and 1.5 of SWD (0.3 and 0.6 of Q) and the corresponding values in the unattended field were 0.6 and 3.2 of SWD (0.4 and 0.8 of Q). Higher values are shown by the groundnut subplots, which crop also suffers from excess water, and by the drier year as well as in the unattended fields. A first approximation is given, still including readily available water at harvest, of minimum water requirements in attended watering for maximum yields. In the drier year, when more irrigation water was applied, an amount equal to 30-50% of these minimum water requirements was lost in evaporation from standing water/wet surface, which is the main unproductive water. More frequent land levelling aiming at minimum standing water in better attended irrigation and farm management (e.g. weeding) are priority measures proposed. The quantitative on-farm water waste determinations represent the innovative content of this paper. Knowing precisely how large the problem is and being able to quantify its components will contribute much to the arguments of those who wish to take the proposed measures.     

Breeding for bean fly resistance in common bean (Phaseolus vulgaris L.): a review

The bean fly (Ophiomya spp) is the most important yield limiting insect pest of common bean in Africa. The insect pest can cause complete crop loss affecting bean production and productivity under epidemic conditions. Effective control of bean fly is essential for sustainable bean production Africa. The overall progress, opportunities and challenges of the bean fly control strategies. The biology and ecology of bean fly and the economic importance of the insect pest is presented as well as the existing controlling strategies, with an emphasis on the breeding on breeding strategies used, research progress achieved challenges and opportunities. In conclusion, significant research progress have been made in breeding for bean fly resistance evident by identification of breeding lines, understanding resistance mechanism and development of breeding strategies. However, there is a need for further research to validate the available information and also explore new breeding methods such molecular breeding which has not been explored at present. Such studies will accelerate breeding for bean fly resistance.     

Including 793/B type avian infectious bronchitis vaccine in 1-day-old chicken increased the protection against QX genotype

Tropical Animal Health and Production - Infectious bronchitis virus (IBV) is a highly infectious pathogen, which affects the respiratory tract, reproductive system, and kidney of chickens. Many...     

Survival and fertility rate of cooled dromedary camel spermatozoa supplemented with catalase enzyme

The present study was planned to study the effects of addition of different concentrations of catalase enzyme (0, 250, 500 and 1,000 IU/ml) to cooled dromedary camel semen extended with tris-yolk-fructose extender on semen quality during storage at 5 C for up to 5 days. Conception rates of she-camels artificially inseminated with whole fresh or extended cooled dromedary camel semen with or without 500 IU/ml catalase enzyme were also estimated. The results showed that addition of catalase enzyme at concentrations of 250 or 500 IU/ml to extended cooled dromedary camel semen significantly increased (P<0.01) the percentage of sperm motility and significantly decreased (P<0.01) the percentages of dead spermatozoa, sperm abnormalities and acrosomal damage. The highest (P<0.01) percentage of sperm motility was recorded with extended cooled dromedary camel semen supplemented with catalase enzyme at a concentration of 500 IU/ml, and the lowest (P<0.01) value was recorded with catalase enzyme at a concentration of 1000 IU/ml. On the other hand, the lowest (P<0.01) percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa were recorded with extended cooled dromedary camel semen supplemented with 500 IU/ml, and the highest (P<0.01) values were recorded with catalase enzyme at a concentration of 1,000 IU/ml. Advancement of the storage time at 5 C significantly decreased (P<0.01) the percentage of sperm motility and significantly increased (P<0.01) the percentages of dead spermatozoa, sperm abnormalities and acrosomal damage of spermatozoa. Moreover, the conception rates of she-camels artificially inseminated with whole fresh, extended cooled dromedary camel semen free-catalase enzyme and extended cooled dromedary camel semen supplemented with catalase enzyme at a concentration of 500 IU/ml were 46.15, 22.22 and 37.50%, respectively. In conclusion, the results show that addition of catalase enzyme at a concentration of 500 IU/ml to semen extender can be used as an agent for prolongation of dromedary camel sperm cell survival during storage at 5 C.     

Comparisons among two serological tests and microscopic examination for the detection of Theileria annulata in cattle in northern Sudan

We tested the agreement between microscopic examination (ME), a surface protein-detecting enzyme-linked immunosorbent assay (TaSP ELISA) and an indirect fluorescent assay (IFA) for detection of Theileria annulata in 2661 naturally infected cattle from northern Sudan (samples collected between June 2001 and July 2002). In the ME, we detected piroplasms in 364/2661 cattle (14%), and the kappas between the ME and the serological tests were poor (TaSP ELISA 10%; IFA 8%). The TaSP ELISA detected 885/2661 cattle as positive, and the Rogan-and-Gladen corrected true prevalence of this sample was estimated to be 30%. The relative sensitivity and specificity of the IFA (compared to the previously validated TaSP ELISA) were 70.7% and 81.8%, respectively.     

Detection and molecular characterization of viruses associated with tomato yellow leaf curl disease in cucurbit crops in Jordan

In this study, Tomato yellow leaf curl Sardinia virus (TYLCSV) and the strains Israel and Mild of Tomato yellow leaf curl virus (TYLCV-IL, TYLCV-Mld) were detected for the first time in four cucurbit crops in Jordan by nested polymerase chain reaction (nPCR). These viruses cause the tomato yellow leaf curl disease (TYLCD) in tomato. Cucumber, squash, melon and watermelon plants inoculated with TYLCV-IL[JO:Cuc], TYLCV-Mld, TYLCSV-IT[IT:Sar:88] and the Jordanian isolate of TYLCV (TYLCV-JV) did not show disease symptoms. However, virus-specific fragments were detected in uppermost leaves of symptomless plants by nPCR. A whitefly transmission test showed that Bemisia tabaci could transmit TYLCV-Mld from cucumber into tomato and jimsonweed plants. However, all infected tomato plants remained symptomless. In addition, results of semi-quantitative PCR (sqPCR) analysis showed that the relative amount of TYLCV-Mld DNA acquired by B. tabaci from cucumber plants was less than that acquired from tomato plants.