PROTECTION COMPLEXES’ EFFICIENCY IN FIGHTING AGAINST ONION DOWNY MILDEW (PERONOSPORA DESTRUCTOR), ATTACK ON LEAVES

  • Alexandra Becherescu U.S.A..M.V.B. Timişoara, Calea Aradului, nr. 119, Timişoara
Keywords: crop, protection, yield

Abstract

The economic efficiency of the treatments applied in the integrated fighting against the main diseases and pests represent the index for the protected yield value, in comparison with the cost of fighting processes or the damage value, the reference being made to the cost of the phyto-sanitary treatments. The apparition of the attack caused by a pathogen agent in crop does not require an immediate intervention by all means. So, we have the notion of „economic damage threshold” or tolerance, that represents actually the attack level assessment for which the fighting against is profitable. Treatments’ efficiency is proved by the improvement index of yield results and by the recovering of the expenses for treatments. The analysis of the experimental data from 2003-2005 provides the influences exerted by the protection complexes in the seven variants upon the pathogen Peronospora destructor (Berk.) Casp. – attack on leaves, their efficiency being expressed in percentages ranging between 81.8% (V4) and 99.2% (V6). The biggest values belong to the variants V5 - Ridomil Gold MZ 68 WP 0,25% + Victenon 50 WP 0,075% and V6 Ridomil Gold Plus 42,5 WP 0,3% + Mospilan 20 SP 0,025% (99.1%, respectively 99.2%), and the lowest values to V4 - Folpan 80 WDG 0,15% + Karate Zeon 0,02% (81,8%) and V1 - Trichodex 25 WP 0,2% + Victenon 50 WP 0,05% (85,8%). We may notice that there is not a direct proportionality between efficiency values and yield in all variants. For example, variant V5 - Ridomil Gold MZ 68 WP 0,25% + Victenon 50 WP 0,075% (99,1% → 26,8 t/ha) in comparison with V6 - Ridomil Gold Plus 42,5 WP 0,3% + Mospilan 20 SP 0,025% (99,2% → 25,7 t/ha) and V7 - Dithane M 45 0,2% + Fastac 10 EC 0,02% cu 91,0% (91% → 17,9 t/ha). Yield difference or the yield saved after treatments exerts a direct influence upon the improvement index of yield results, the biggest values belonging to the variants V5 - 15.487,58 lei/ha and V6 14.416,47 lei/ha, and the lowest value to V7 - 7221,28 lei/ha. As conclusion, we may observe the superiority of the protection complexes from V5 - Ridomil Gold MZ 68 WP 0,25% + Victenon 50 WP 0,075% and V6 - Ridomil Gold Plus 42,5 WP 0,3% + Mospilan 20 SP 0,025% upon the pathogen Peronospora destructor (Berk.) Casp. – attack on leaves.