Çukurova Bölgesi koşullarında, potasyum gübrelemesinin pamuğun tarımsal ve lif teknolojik özelliklerine etkisi üzerine bir araştırma

TEZ3237Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1998.Kaynakça (s. 48-52) var.iv, 52 s. ; 30 cm.

Predicting the number of nymphal instars plus new-generation adults of the Sunn Pest from overwintered adult densities and parasitism rates

The present study evaluated the effect of overwintered adult density and egg and adult parasitism rates on the new-generation population densities of the Sunn Pest (Eurygaster integriceps Put.) under field conditions. We quantified the abundance of overwintered adult densities and egg and adult parasitism rates in 20 one-ha unsprayed wheat fields in southeastern Turkey to assess their impact on nymphal instars, plus new-generation adult densities. The number of overwintered adults per square meter and the percent of egg parasitism rates were positively and negatively correlated with new-generation densities of the Sunn Pest, respectively. The results of multiple regression analysis produced the equation Y = 15.037 + 8.287 OW (overwintered adult) - 0.235 egg PR (parasitism rate). The findings suggest that the egg parasitoids may suppress nymphal instars plus new-generation adult densities of the Sunn Pest. The findings also suggest that the present formula can be used to determine the spraying areas in which densities reach economic threshold for the integrated Sunn Pest management program in wheat fields in Turkey

Predicting the number of nymphal instars plus new-generation adults of the Sunn Pest from overwintered adult densities and parasitism rates

The present study evaluated the effect of overwintered adult density and egg and adult parasitism rates on the new-generation population densities of the Sunn Pest (Eurygaster integriceps Put.) under field conditions. We quantified the abundance of overwintered adult densities and egg and adult parasitism rates in 20 one-ha unsprayed wheat fields in southeastern Turkey to assess their impact on nymphal instars, plus new-generation adult densities. The number of overwintered adults per square meter and the percent of egg parasitism rates were positively and negatively correlated with new-generation densities of the Sunn Pest, respectively. The results of multiple regression analysis produced the equation Y = 15.037 + 8.287 OW (overwintered adult) - 0.235 egg PR (parasitism rate). The findings suggest that the egg parasitoids may suppress nymphal instars plus new-generation adult densities of the Sunn Pest. The findings also suggest that the present formula can be used to determine the spraying areas in which densities reach economic threshold for the integrated Sunn Pest management program in wheat fields in Turkey

Economic threshold for the sunn pest, Eurygaster integriceps Put. (Hemiptera : Scutelleridae), on wheat in southeastern Turkey

The sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), is the most important insect pest of wheat and barley in Turkey. To redefine an economic threshold (ET) for the sunn pest, we determined the yield loss as the result of white spike damage caused by overwintered adults and kernel damage by nymphs and new-generation adults in wheat fields. Studies conducted in 17 one-ha insecticide-free wheat fields showed that white spike damage occurred at low levels (0.1-1.7%). Regression analysis was used to assess the relationship between overwintered adult density and white spike damage and between percent kernel damage and sedimentation value. The relationship between overwintered adult density and white spike damage was not significant in bread and durum wheat. Mean kernel damage was 2.2% and 6.6% in bread wheat and 8.0% and 2.8% in durum wheat in 2002 and 2003, respectively. There was a positive relationship between nymph and new-generation adult density and kernel damage using regression analysis in bread and durum wheat. Sedimentation values were 18-82 and 7-89 in 2002 and 2003 in bread wheat, and 9-22 and 9-28 in 2002 and 2003 in durum wheat. No effect of sunn pest density on gluten strength up to 2.1% kernel damage in bread wheat or up to 0.9% kernel damage in durum wheat was detected, but kernel damages greater than these levels limited dough quality. When these limit values were used, economic thresholds were 8.1 and 9.2 nymphs/m(2) in bread and durum wheat. The current ET (10 nymphs/m(2)) may be lowered to 8-9 nymph/m(2) for some wheat varieties and regions, especially for low-yield levels (approximately 2000-2500 kg/ha) in bread wheat but may still be valid for durum wheat