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. |
