The main objective of this work is to evaluate
the relationship between the pest population, Parlatoria
oleae (Colvee), through pest activity peaks in
October/November; April and July on the yield loss of
seedy Balady mango trees at Esna district, Luxor
Governorate, Egypt through two seasons (2016/2017 and
2017/2018). Data revealed that the increment of
population density caused gradual decrease of the yield
of mango fruits, consequently increased the percentage of
yield loss when the data of the yield were colligated with
the pest population peaks in October/November; April
and July months through 2016/2017 and 2017/2018
seasons. Increasing one individual of pest per leaf caused
a reduction of the mango yield by 2.53, 2.51 and 4.59
kg/tree and 2.25, 2.19 and 2.88 kg/tree through the
periods of population abundance of the two seasons,
respectively. Accordingly, increased yield loss
percentages by 1.05, 1.04 and 1.90% and 0.87, 0.84 and
1.10% occurred during the mentioned periods of the two
consecutive seasons (2016/2017 and 2017/2018),
respectively. These results confirmed that P. oleae
population during the peak of April resulted the least
expected amount of mango fruits yield and the greatest
loss in mango yield. On contrary, the peak during July
was less effective, causing the highest expected yield and
the lowest reduction in mango fruits yield of the two
seasons.
Generally, the reduction in yield of mango fruits is known
to be a summation of many factors including the rate of
infestation, time of infestation and variety ability to
infestation. |
