Biological Control of Cotton Mealy Bug (Phenacoccus solenopsis) in Pakistan
Muhammad Waqas Yonas1*, Kashif Umar1
1Department of Agronomy, University of Agriculture Faisalabad, Pakistan
1Department of Entomology, University of Agriculture Faisalabad, Pakistan
Correspondence E: Mail: [email protected]
Gossypium hirsutum L. is one of the chief cash crops of the country which has play significant role in the economy of the Pakistan. In general, its contribution to gross domestic products (GDP) is 1% and in agriculture 5.2%. Cotton crop is a multi-purpose crop. Its products are used in large quantity in the textile and oil industry. Cotton crop heavily attacked by the different pest which results in the reduction of crop yield in Pakistan 30-40%. In the whole growing season, it is attacked by 1326 species of pest including vertebrates and invertebrates. Phenacoccus sp. is also damage the cotton crop through feed on the sap and release the poisonous material which cause hurt, coiling and drying of the leaf which costs in the production of fruit and drastically reduction in the yield of cotton crop. The Phenacoccus sp. is polyphagus insect pest reported on various type of 53 families, which is belonging to the 154 different plant species of that families.This mealy bug pest has a widespread geographical dispersion with its basis in Central America. After that P. solenopsis also reported by the Caribbean, Chile, Argentina and Brazil. Phenacoccus solenopsis defined as a very offensive insect pest in Pakistan and India.
In Indo-Pak, Phenacoccus sp. has triggered prevalent and cause serious injury to the cotton crop It can injure the bud formation, branches, flower, bolls, foliage, main stem etc. If it is left uncontrolled can be source of complete wilting of the plant and forcefully opening of the undeveloped bolls. Various survey on monthly basis in the cotton growing areas for the insect pest prevalence, presented that the insect pest of mealy bug had feast to different areas with more intensity throughout past year, display our impact in the form of dried cotton plants in square form in the field. This pest also found to be infested the many other host plant like Simbl, Aksan, Night jasmine etc.
In the course of studies, Phenacoccus solenopsis was seriously confronted by the nymphal endoparasitiod, Aenasius bambawalei. Though different parasitoids and hunters have been recognized to attack Phenacoccus solenopsis. Three types of wasps (Chalcaspis arizonensis, Cheiloneurus sp., and Aprostocetus minutus) were revealed to attack on the P. solenopsis pest of cotton. In India, another anonymous species of the retiring endoparasite, Aenasius sp. was specified to the attack on the pest P. solenopsis. A new parasitoid species Aenasius bambawalei, which has been recognized as a very important contender to control the mealy bug by biologically. This parasitoid can to parasitized the P. solenopsis up to 72% of total population of it.
Phenacoccus sp. is a bisexual specie which produce multiple peers in a year. Like others species of the mealy bug, this species is famous for its morphology of its adult female. Adult female of this species is covered with a waxy powdery secretion, with six pairs of crosswise dusky bands present on the thorax. A sequence of the waxy filament prolonged from throughout the border of the body with the couple of the final filament protracted. The ovisac of cotton mealy bug is drawing up from fluffy, fine-textured wax strings. Length and width of cotton mealy bug adult female is 2-5 mm and 2-4 mm respectively. Adult female is capable to produce up to 600 eggs.
Favorable condition for pest development
Different studies on the growth of insect pest of mealy bug shows that high temperature and long sunshine hour had a positive impact on the Phenacoccus solenopsis and high RH and rainfall had negative impact of the pest development. Phenacoccus solenopsis preferred to grow in 860mm precipitation annually. It can tolerate minimum 0°C to maximum temperature 45°C. It preferred developed in the 42 N to 31S latitude.
Phenacoccus solenopsis has a wide range of alternate host plant ranging from herb weeds to woody trees and plants. P. solenopsis pest has been recorded as insect pest of 154 different host plants and tress species from which 20 agronomic field crops (Sesame and Common tobacco), 64 herb weeds (Aksan and Kandiari boti), 45 Horticultural ornamental plants (Tickberry and Night jasmine), 25 shrubs and trees (Karir and Simbal) which is belonging to utmost 53 different plant species.
Nature of damage
Phenacoccus solenopsis is polyphagous sucking insect pest with incomplete transformation. It is the unusual insect pest which have wide range of host. It has a waxy defensive covering on the abaxial side which pawn the potential death factors. It attacks the host plant by lapping cell sap of the plant phloem tissues and conceal the honeydew which produce grimy mold on the outward of the plants leaves, thus stopping the photosynthesis process of the plant and finally resulting in the demise of the cotton plant tissues.
Mealy bug invasion result in the extraction of cell sap from the leaves of the plants. After the extraction leaves turn yellow and become folded and deformed, which lead to reduction in the cotton plant vigor, drop of the leaves and fruits and ultimately the demise potential of the plant. Phloem suckling affect the budding part of the plant which results in undersized the growth and development of the plant which consequently reduces the size of flowers and size and number of the fruits which ultimately reduced the fruit yield. Different researcher stated that infested fields of cotton mealy bug shows different type of symptoms, leaves of the cotton plants turns in to the yellow color, grimy mold also present on it, necrosis of leaves, wilting and anomalous leaf fall at the end. In the fruits of the cotton crop irregular patterns, discoloration and grimy mold are formed on the fruits and ultimately premature fruit are drop. Growing points of crop (buds) due infestation of pest become impaired, grimy mold also present due to which dieback of the buds occurred. Roots and stem of the cotton crop are become impaired and stem are covered grimy mold, reduced root system is present in infested fields, furthermore boring in the roots and stem done by the Phenacoccus solenopsis.
The supervision of the Phenacoccus solenopsis pest is very vital to save billion-dollar business of cotton crop and its control strategies appear too predictable to override the insect pest population of cotton mealy bug below the threshold level. It is observed most venerable stage of the cotton mealy bug is larval stage which is suitable to effect by the environmental factors. It can be control easily by applying different control measures. The control measures of cotton mealy bug are the traditional, biological, chemical. The operational flexibility and sequence of the growth stages allow the Mealybug to pawn single type or any other type of control strategies effectively. So IPM are the main strategies in contradiction of the mealybug. Here we discussed only biological control measures.
Plant Based Insecticide
To make the crop plant unpalatable for the insect pest plant extract also use as insecticide for the pest, this extract act as repellent. First and foremost, Azadirachta indica seed abstract is used for control of insect pest which is similarly effective. Some other plants are also very effective to control various kind of insect in which tobacco, dhatoora and Malia azadirachta,. Plant based insecticides are environmentally compatible and harmless and also safe for the mankind and animal are use at lesser degree in comparison with other method of pest management. Plant extract are decomposable, less poisonous to a wide diversity of life, cheaper and helpful to biodiversity preservation.
Organism Based Control
Various natural enemies of Phenacoccus solenopsis has been stated from numerous researcher at different part of the world and these are thought to be one of the most important control agents of the Phenacoccus solenopsis programs. Substantial infestation of P. solenopsis may be return of the absent of natural opponents on this aggressive pest. A mainstream of researcher has defined the destructive potential of various hunters and parasitoids. It was stated that biological control procedures were verified effective and harmless to host crop. There are several organisms which is used to control or counter the cotton mealybug such as Aenasius bambawalei, Promuscidea unfasciativentris Girault, Cryptolaemus montrouzieri, , Crysoperla carnea and Brumus suturalis. The thoughtful eruptions of P. solenopsis results in the absence of their natural enemies and classical biological control has been considered as the most suitable method for the supervision of many striking mealybug species in various parts of the world.
It is noticed that if once the crop field is infested by the cotton mealy bug, turn out to be difficult task to overcome pest. Effectiveness of both type insecticide is reduced due to the waxy covering on the dorsal side of the mealy bug pest. However, to increase the effectiveness of extracted and artificial insecticides, some footstep should be taken. unnecessary plant should be removed because it provides alternate host. severely damaged plant should be buried under the soil. Sequential sprays should be done to reduce the population which can be water and surface solution. Although the chemical control is so far best solution to control it but the researchers should adopt biological technologies like to promote Aenasius bambawalei laboratory at field level to overcome the problem of cotton mealy bug in Pakistan.