Flowering, Yield and Fruit Quality of Balady Mango Seedling trees as influenced by Parlatoria oleae (Colvee) Infestation Rate

Abstract

The present study was conducted to investigate some flowering, yield and fruit quality (fruit physical and chemical properties) measurements of twelve years old Balady mango seedling trees grown in clay- loamy soil under surface irrigation system of private orchard located at Esna district, Luxor Governorate as affected by Parlatoria oleae infestation rate during two successive experimental seasons through duration from early September 2016 till mid August 2018 years. Data obtained during both (2016/2017) and (2017/2018) seasons revealed that dates of first, full bloom and harvesting took place earlier in the uninfested trees (control) as compared to the analogous measurements of either slightly or severely infested ones. Moreover, two yield parameters i.e., number and weight (kg.) of mature fruits harvested per each individual tree were obviously decreased by both P. oleae infestation rates as compared to those of the uninfested trees (control). As for the impact on both fruit physical and chemical characteristics, the uninfested trees exhibited an obvious improve in (average fruit dimensions, volume and weight) and (total soluble solids, total soluble solids / acidity ratio, total sugars, reducing sugars and sucrose contents) associated with lower total acidity %. On the other side, the heavily P. oleae infested trees showed significantly the highest reduction in all studied yield and fruit qualities measurements, except with total acidity %, whereas the trend took the other way around as compared to the free and slightly infested trees. Besides, P. oleae was more active through autumn months particularly during October and November of 1st and 2nd seasons, respectively. However, the reverse was true during winter months whereas the least values of P. oleae total population density were detected in both seasons, regardless of infestation rate. Concerning, the relationship between the differences in reduction % in a given desirable parameter from one hand and different infestation rate from the other estimated values of the simple correlation and regression coefficient pointed out the highly significant positive relationship between the increase of one insect per leaf and the increase in reduction of all tested yield and fruit qualitites measurements, except total acidity percentage.