No abstract

Potato is an important tuberous vegetable crop in Ethiopia. However, its production is constrained by arthropod pests, nutrient depletion of soil and diseases. Among arthropod pests, two-spotted spider mite (TSSM, Tetranychus urticae) is one of the major arthropod pests affecting potato production and contributing to low yield in eastern Hararghe, Ethiopia. To tackle this problem, the survey was undertaken to assess the distribution, farmers' management practices and their perception of TSSM on the irrigated potato. The data were collected from ninety-six potato producers during the dry season in Haramaya, Kombolcha, Kersa, and Metta districts of Eastern Hararghe Zone by interviewing, observing and recording from October to March in 2018/2019. The meteorological data were obtained from the National meteorological agency, Jijiga station. The number of TSSM/potato plants, prevalence, incidence and severity levels of potato were analyzed using three-stage nested design. Farmers' perceptions and practices were analyzed by using descriptive statistics, while the relationship of weather factors and altitude with the status of TSSM was analyzed using SPSS software program version 16.0 and determination of Pearson correlation was done using SPSS statistical software. This assessment confirmed that TSSM was found in all the districts with variation in number per potato leaves, incidence and severity levels. The highest incidence (37.88%), severity (3), number of TSSM/potato (39) per plant was scored from the Haramaya district and the lowest was recorded from Kombolcha district. Based on the observation and response of the respondents, the TSSM was mostly prevailed in autumn (44.79%) but was the lowest in spring seasons (6.25%). It severely affected potato production at flowering stages (44.2%). But the lowest damage was at the seedling stage (7.4%). The number, prevalence, incidence and severity of TSSM was the highest in Haramaya and the lowest in Kombolcha districts. Data on farmer's perception also showed that 60% of them recognized TSSM on potato plants. The linear correlation coefficient indicated that the incidence (r=-0.546, Y=-0.548X+38.7), number of TSSM/potato plant (r=-0.847, Y=-0.06.232X+38.24) and severity level (r=-0.431, Y=-0.0221X+2.805) was decreased as rainfall intensity increased. The studies suggested that the provision of a resistant variety of potato, chemical pesticides, water supply will help the farmers to increase the production and productivity of potato by decreasing the yield losses due to TSSM. Further research on the seasonal abundance, effect of microclimate, natural enemies and management practices on the population dynamics of TSSM in the major potato growing areas of the eastern part of Ethiopia was suggested from the study.

Antestia bug (Antestiopsis intricata) is the major coffee insect pest affecting coffee productions in Ethiopia.Therefore, the study was carried out to evaluate entomopathogenic fungi based management options for antestia bug control. The efficacy test of entomopathogenic fungi was done under laboratory condition in Jimma Agricultural Research Center, Entomology and Pathology laboratories. The entomopathogenic fungi isolates were brought from Haramaya University and Ambo Agricultural Research Center. Seven isolates of Beauvaria bassiana (DLCO-12, APPRC-0247, DLCO-90, DLCO-56, DLCO-76, PPRC-44BC, and PPRC-27J) and four isolates of Metarhizium ansopliae (PPRC-51, DLCO23A, DLCO-91 and PPRC-02BC) species were tested for germination. Completely Randomized Design with three replications and probit analysis were used for data analysis by using SAS, GenStat and Microsoft excel. Eight isolates: APPRC 0247, DLCO 90, DLCO 56, DLCO 76, PPRC-44BC, PPRC-27J, PPRC-51 and PPRC-02BC which recorded higher germination were used for pathogenicity test against antestia bugs. All the tested isolates killed antestia bugs but their levels of efficacy differ across exposure time. Among tested isolates, PPRC-44BC and PPRC-27J registered complete mortality against antestia bugs and lower median lethal time, LT 50 (9.98 and 10.98 days, respectively). As a result these were taken as promising isolates and used for further isolates rate test. PPRC-44BC and PPRC-27J isolates applied at 1x10 8 conidia ml -1 killed all the tested antestia bugs in shorter exposure time. Even though PPRC-44BC and PPRC-27J isolates showed promising results under laboratory conditions, it needs further investigations on its formulation and under field conditions. Isolations of biocontrols from natural coffee growing areas and the effect of biocontrols against natural enemies should be studied.

Field experiment was set up in November 2011 and continued up to March 2013 on 324 m 2 backyard garden plot of a farmer's residential area. The experiment was laid in 6 m × 6 m Latin square design. The treatments were polyethelene bag covered wooden sticks, chlorpyrifos 48% E.C. treated and polyethelene bag covered wooden sticks, Masea lanceolata treated and polyethelene bag covered wooden sticks, chlorpyrifos 48% E.C treated planting hole, M. lanceolata treated planting hole and untreated check. Every three months, termite infestation, damage and damage severity were recorded. The chlorpyrifos 48% E.C. treated polyethelene bag covered wooden sticks (0.2) and the chlorpyrifos 48% E.C. treated planting hole (0.2) protected termite infestation and damage throughout the study period starting from six months after application of treatment. In the rest of the treatments, damage progressed towards the end of the experiment with no significant difference amongst them. The severity of damage was significantly lower in chlorpyrifos 48% E.C. treated polyethelene bag covered wooden sticks (3 and 1.3) and chlorpyrifos 48% E.C treated planting hole (4.4 and 2.3) than the other treatments starting from twelve to eighteen months after application of treatments. Conclusively, chlorpyrifos 48% E.C. treated polyethelene bag covered wooden sticks and chlorpyrifos 48% E.C treated planting hole protected the wooden construction materials from both genera of termites. However, the chlorpyrifos 48% E.C. treated polyethelene bag covered wooden sticks was superior in providing longer duration of protection and reduction of environmental hazards. In the former treatment, no chemical was in contact with soils that saves not only contamination of soils and ground water but also reduced the rate of the biodegradability of the chemical.