Abstract:
The mango seed borer, Noorda albizonalis Hampson, completed its life cycle from 28 to 41 days.
The eggs were laid in masses on the fruit apex and hatched after 3 to 4 days.
The insect passed through five larval instars with a total development period that ranged from 14 to 20 days.
The pre-pupal and pupal stages lasted from 2 to 3 and 9 to 14 days, respectively.
Longevity of adult was from 8 to 9 days.
The insect successfully developed into adults when reared on both flesh and seed of 'carabao' mango.
However, individuals reared on the flesh were respectively bigger, more fecund and have longer development.
Four other mango varieties supported the complete development of the insect.
Fruit infestation was observed in different mango growing areas of the country.
This occurred as early as 45 to 55 days after flower induction and continued up to fruit maturity.
Greater percent damage was however, observed on medium size fruit, 75 to 85 days after induction.
Insect population based on fruit infestation record was high in summer with the peak of abundance observed either in March or April.
Availability of mango fruit stood out as the most important limiting factor that influenced the size of insect population.
In the absence of this fruit, adults failed to reproduce in other parts of mango nor on other fruit suspected as alternate host of the borer.
Two species of parasitoids and one species of predator were observed to attack the immature stages of the borer. Trichoqramma chilonis and T. chilotraeae were recorded as egg parasites while a vespid wasp, Rhychium attrisimum was found as important larval predator.
Based on economic analysis, the most effective insecticides for the control of the mango seed borer were cyfluthrin and deltamethrin.
|