M. M. H. KHAN
Department of Entomology, Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh
M. N. HOSSAIN
Department of Entomology, Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh
Abundance, Incidence, Mealybugs, Papaya, Paracoccus marginatus
Dumki, Bouphal, Dashmina, Patuakhali, Mirjagonj, Amtali, Kalapara and Kuakata of Patuakhali and Barguna districts of Bangladesh
Pest Management
Survey on the incidence, abundance and damage potential of mealybug on papaya: Studies were carried out in the farmers’ field and homestead garden of Patuakhali and Barguna districts to collect data on the incidence, abundance and damage symptoms of mealybugs infesting papaya from September 2018 to June 2019. Eight locations viz., Dumki, Bouphal, Dashmina, Patuakhali, Mirjagonj, Amtali, Kalapara, and Kuakata were selected. Two villages from each location were selected considering papaya cultivation. A total of 80 plants taking five (5) papaya plants from each village were selected randomly. All the plant parts were carefully observed and recorded papaya mealybug population, its infestation and damage symptoms. The random selection and collection method was followed for the study providing every sampling unit an equal chance to be chosen. Every leaf was considered as a single sampling unit and a total of six leaves along with their twigs (two leaves each from lower, middle, and upper canopy) were sampled from randomly selected plants. Five plants were sampled randomly and considered as five replications from each location to avoid any errors. The leaves were cut with a sharp knife, placed in plastic sealed carry bags, and labeled with the date and locality of the collection. The samples thus collected were brought to the Entomology laboratory for sorting and population counts for mealybug for each plant. Later on these specimens were kept in glass jars and covered with muslin cloth on top for rearing the mealybug and were observed the presence of any natural enemies emerging from such infested specimens. Data on the number of infested and healthy plants per location, number of infested leaves per plant, number of fruits per plant were recorded through observation of individual plants in each location. Population abundance of P. marginatus was measured by counting the number of egg and immature groups under a stereo microscope.
Percentage of P. marginatus on the fruits and leaves was calculated by dividing the number of fruits/leaves damaged by the total number of fruits/leaves in each plant individual by:
P = n/N x 100
with P = percentage damage rate, n = number of infested fruits/leaves per plant, and N = total number of fruits/leaves per plant.
Effect of some control approaches for managing mealybug on papaya: An experiment was laid out in a randomized complete block design with 3 replications. Seven treatments viz., T1 = Removal of infested leaves with petioles + application of Nitro 505EC @ 1 ml/L of water, T2 = Application of Nitro 505EC @ 1 ml/L of water, T3 = Removal of infested leaves with petioles + Biotap plus extra 95EC @ 0.2 g/L of water, T4 = Biotap plus extra 95EC @ 0.2 g/L of water, T5= Removal of infested leaves with petioles + application of voliam flexi 300SC @ 0.5 ml/L of water, T6 = Application of voliam flexi 300SC @ 0.5 ml/L of water and T7= Untreated Control were used. Data were collected on the number of mealybugs per plant, leaf and fruit, the number of infested leaves and fruits/plant.
Data were analyzed by using WASP software following analysis of variance (ANOVA) and means were separated by CD (critical difference) values.
J. Asiat. Soc. Bangladesh, Sci. 47(2): 109-120, December 2021
Journal