To study the effect of compatible pesticides spray against major pests and diseases of Apple

Abstract

A two year field trial at Shalimar campus, SKUAST-Kashmir was conducted to study the compatibility of various insecticides and fungicides against major pests and diseases of apple. Insecticides and fungicides are recommended to be sprayed separately without admixing suspensions involving huge labour and time components. Different pesticides and fungicides were sprayed with 
at five different phenological stages (fruit-let, fruit development stage-I and fruit development stage II). Standard controls comprising of recommended sprays were also given at these stages for comparison, in addition to unsprayed check. Observations with respect to foliage and fruit scab, Alternaria leaf blotch and percent mortality of European red mite (ERM) and San Jose Scale (SJS) were recorded at fruit-let, fruit development stage-I and fruit development-II stages. The pesticidal combination exhibiting physical incompatibility was discarded in the initial phase. Combined spray of fungicide and insecticide proved equally effective in controlling diseases and pests of apple in different stages. The experimental plants sprayed with mixtures of fungicides and insecticides at recommended concentrations exhibited significant reduction in apple scab, ALB, EMR and SJS in comparison to unsprayed check at fruit-let stage. Results revealed that treatment T5 (difenconazole + phosalone) proved superior in minimizing foliar scab incidence and intensity whereas treatment T3 (difenconazole + chlorpyriphos) and T16 (difenconazole) had minimum incidence (0.80%) and intensity (0.30%) of fruit scab. The trees sprayed with hexaconazole followed by chlorpyriphos (T9) result lowest disease incidence (0.23) of ALB and lowest intensity (0.17) was found in Haxaconozol followed by Milbactin (T10). T4 (Difenconazole + Milbactin) proved most effective in inflicting maximum ERM mortality (68.6%) and was at par with T7 (65.6%) followed by T14. Treatment T1 (Haxaconozole + Milbectin) shows 57 per cent mortality of SJS and was at par with T3 (Difenconazole + Chlorphriphos) and T12 (Chlorpyriphos) treatments. At fruit development stage-I, all the treatments controlled apple scab, ALB, ERM and SSJ significantly as compared to unsprayed check (table 2). T5 (Zineb +Chlorpyriphos) had least foliage scab incidence (2.63%) and T13 (Mancozeb) showed lowset intensity (0.70%), whereas T5 (Zineb + Chlorpyriphos) exhibited least fruit scab incidence (6.50%) followed by T8 (Mancozeb followed by Chlorphriphos) and lowest intensity were recorded in T2 (Mancozeb + Chlorpyriphos) and T8 (Mancozeb followed by Chlorphriphos) (02.03%). ALB incidence was significantly controlled by T3 (Mancozeb + Dicofol) and intensity was significantly controlled by T1 (Mancozeb +Quinalphos) followed by T2. Percent mortility of ERM was highest by T12 (Dicofol) (80.4 %) followed by treatment T5 (Zineb + 
Chlorpyriphos) (75.9) per cent. In case of SJS, treatment T10 (Quinalphos) and T7 (mancozeb + Quinalfos) was most promising with 79.3 and 78.3% mortality, respectively. At fruit development II, all the treatments significantly controlled apple scab, ALB, ERM and SJS in comparison to unsprayed check (table 3). Least leaf scab incidence and intensity was showed by treatment T5 Bitertinol+ Propargite (8.63 and 2.41 %, respectively) However, least fruit scab incidence was observed in trees sprayed with T3 (Flusilozole + Summer spray oil) while treatment T2 (Flusilozole + Propargite) showed lowest fruit scab intensity of 3.27 per cent. Bitertinol + summer spray oil (T6) 
sprayed trees had least ALB incidence (5.97%) while T7 (Difenconazole + Dimethoate) had least ALB intensity (2.65%). Percent mortility of ERM was highest by T14 Propargite effectively controlled ERM and was at par with treatment T15 and T8. Similarly In case of SJS treatment T7 (Difenconazole with Dimethoate) and T1, T4, T6, T9, T10 and T13 showed statistically similar performance. Thus compatible chemicals can effectively minimize labour, time and inputs.