This study investigates the reactions of four summer pumpkin cultivars (cvs. Çağlayan, Mert Bey, Sena Hanım, TG38) to root and crown rot caused by Fusarium proliferatum by taking into account criteria such as disease severity, plant growth (number of leaves, height, dry and fresh weight of shoot) and the accumulation of phenolic compounds in the roots. Seeds of each cultivar were inoculated with the pathogen and left to develop for 1 month at 25oC in a controlled climate room. The content of phenolic compounds in ethanolic root extracts was determined using high-performance liquid chromatography (HPLC). Cv. Sena Hanım had the lowest disease severity (4.40%) among the cultivars, followed by cvs. Çağlayan (10.62%) and Mert Bey (11.07%). Plants developed from inoculated seeds of cvs. Çağlayan and Sena Hanım had no decrease in the number of leaves and in length, fresh and dry weight of shoots in comparison to the control (plants from non-inoculated seeds), while cv. Mert Bey demonstrated a decrease at very low rates in shoot fresh and dry weight (2.24% and 0.77%, respectively). The phenolic compound that exhibited the highest increase in root extracts of cv. Sena Hanım compared to the control among the cultivars was p-coumaric acid (6.57-fold). This study demonstrates that p-coumaric acid can play an important role in the resistance of pumpkin to seed infestation by F. proliferatum.

This study was conducted to evaluate essential oils from Croton macrostachyus Hochst. ex Delile, Eucalyptus globulus Labill., Allium sativum L., Cymbopogon citratus (DC.) Stapf, Cymbopogon martini (Roxb.) W.Watson, Rosmarinus officinalis L. and Thymus schimperi Ronniger using four concentrations (l mL, 2 mL, 3 mL, 4 mL) and three sprays against potato (Solanum tuberosum L.) late blight disease. Two improved potato varieties were planted using randomized complete block design with factorial combinations in three replications. Analysis of disease incidence means at 53 and 60 days after planting showed highly significant differences between varieties and among sources of essential oils. Furthermore, the combined effect of essential oils and potato varieties on disease severity showed significant differences. Disease severity was maintained from 25% to 48% (Jalene); 13% to 30% (Gudene) with essential oils while it was maintained between 92% and 95% (Jalene); 37% to 38% (Gudene) for control plants. The lowest disease percentage of disease severity was obtained on plants treated with A. sativum for Jalene variety while on plants sprayed with C. macrostachyus, E. globulus and T. schimperi for Gudene variety. The lowest disease progress rate 0.198/day and 0.162/day as well as values of area under disease progress curve 228% days and 93% days were obtained for varieties Jalene and Gudene, respectively. Maximum reduction in mean disease severity was exhibited by garlic for varieties Jalene (28.3%) and Gudene (16.3%), as compared to the control (93.3% for Jalene and 37.5% for Gudene). Therefore, results indicated the potentials of essential oils to minimize effects of potato late blight disease. Communities involved in potato production could use the current results as base line information to find alternative management options for late blight disease which has no effect on human health and environment. However, further investigation is required on essential oils affordability and availability to farmers across different locations.

Verticillium Wilt Disease is one of the most important diseases affecting the rate of cotton yield. There is no economic chemical control for Verticillium wilt, but it is recommended to use resistant varieties to control this disease. This experiment was carried out in a randomized plot design with four replications in the growth chamber to determine the response of some cotton cultivars against a defoliating and non-defoliating pathotypes of Verticilllium dahliae Kleb. In the study, a total of twenty cotton cultivars i.e. the resistant control GIZA 75, the tolerant control CARMEN and the susceptible control ACALA SJ2, defoliating (PYDV6 isolate) and non-defoliating (Vd 11 isolate) pathotypes were used, and cotton varieties were tested using conidial suspension technique. Analysis of variance showed significantly (P