Population Fluctuations of The Phytophagous Mite, Oligonychus mangiferus and its Predator on Mango Trees in Ismailia Governorate, Egypt

Citation: Egypt. Acad. J. Biolog. Sci. (A. Entomology) Vol. 11(4)pp: 8388 (2018) Egyptian Academic Journal of Biological Sciences is the official English language journal of the Egyptian Society for Biological Sciences, Department of Entomology, Faculty of Sciences Ain Shams University. Entomology Journal publishes original research papers and reviews from any entomological discipline or from directly allied fields in ecology, behavioral biology, physiology, biochemistry, development, genetics, systematics, morphology, evolution, control of insects, arachnids, and general entomology. www.eajbs.eg.net Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.


INTRODUCTION
Mango is one of the most nutritionally rich fruits, with a distinctive flavor, smell and taste, especially Egyptian mango is a unique fruit, with an incomparable tropical delicacy.The mango was first brought to Egypt from Sri Lanka.The fruits cultivated by Sri Lankan farmers are, in turn, derived from Indian varieties.Mangoes grow in areas with high humidity, like coastal areas, such as the Nile Delta.They grow best in tropical regions.Ismailia is the main mango-growing area, known for producing the finest mangoes.The soil and climate of Ismailia are especially favorable for the cultivation of Egyptian mangoes.The city of "Beauty and Enrichment" includes vast areas of fertile agricultural land, producing the most famous Ismailia mangoes.The mites (Acari) are important pests of mango in most of the tropical regions of the world and have long been recognized as affecting mango quality and yield, especially when conditions are optimum and their populations explode.The most of species feeding on plant belong to the obligate plant parasitic Eriophyoidea (gall mites, bud mites, erinose mites, rust mites) and Tetranychoidea (false spider mites, spider mites), while a number of species belong to other lineages.(Eupodoidae, Tarsonemidae and single oribatid mites) (Al-Azzazy, 2005;Sarwar, 2014;Sarwar et al., 2013Sarwar et al., , 2015;;Shah et al., 2014).Spider mites within the genus Oligonychus, generally Oligonychus mangiferus (Rhaman and Sapra) infest mango orchards in the specific countries.Nourishing is mainly restricted on the upper area of leaf, alongside the midrib and later on alongside the secondary veins.The areas alongside the veins grow into reddish-brown.Destruction of plants commonly by means of the spider mites is perceived starting from October through February resulting in a decrease of photosynthesis activity equal to 30%.Oligonychus mangiferus was collected from mango trees, Mangifera indica in Ismailia Governorate, (Zaher et al., 1982).The predatory mites associated with phytophagous mite's infestations considered as natural biological control agents to a wide range of economically injurious pests infecting different fruits and crops.They are well known to be capable of regulating and balancing the population of different pests as well as help to gain product free from toxic to keep human health and save the environment from pollution (Taha et al., 2006).
The present work aimed to study the population fluctuations of the phytophagous mite Oligonychus mangiferus and its predator Amblyseius swirskii associated with mango orchard trees at the experimental farm of the agriculture faculty of the Suez Canal University, Ismailia.

MATERIALS AND METHODS
Mean seasonal abundance of the phytophagous mite Oligonychus mangiferus and its predator Amblyseius swirskii with mango trees was studied during two successive years, from October 2014 to September 2016, at the experimental farm of the agriculture faculty of the Suez Canal University, Ismailia, Egypt.In orchard, 30 mango leaves were picked out monthly at regular intervals all over the two successive years of the study.After that, leaves were kept in tightly paper bags, and then transferred to the laboratory for examination.Mites were counted for the upper and lower surfaces of each leaf by using stereomicroscope.The densities of mites were assessed as total number per 30 leaves.According to Kumar et al. (2015), the total numbers of adult mite stages were counted in 2.5 cm 2 area of the leaf underside.While, the predatory mites were counted in the whole leaf area as reported by Poe (1980).Daily mean, maximum and minimum temperature (°C) and mean relative humidity (R.H. %) was obtained from the central laboratory for Agricultural Climate, Agricultural Research Center, Ministry of Agriculture and Land Reclamation.

Statistical Analysis
The Mean abundance (±SE) of the individuals per leaf was calculated.Analysis of variance followed was applied for studying the significant differences regarding the effects of temperature and relative humidity R.H.% on the abundance of the spider mite and its predators.

RESULTS AND DISCUSSIONS
Mean abundance (±SE) of O. mangiferus and its predator A. swirskii on mango trees during two successive years, from October 2014 to September 2016, at the experimental farm of the agriculture faculty of the Suez Canal University, Ismailia, are shown in Tables (1, 2) and Figures (1, 2).Results showed the presence of O. mangiferus during the two successive years of the study in the experimental farm of the agriculture faculty of the Suez Canal University, Ismailia, Egypt.In the first year of study, extended from October 2014 to September 2015, the highest mean abundance of O. mangiferus was 2.96 ± 0.6 recorded in summer and the lowest population was recorded in autumn (0.6 ± 0.11).In the second year, extended from October 2015 to September 2016, the mean abundance of O. mangiferus increased to 3.43 ± 0.7 in the summer season but decreased to 0.7 ± 0.1 & 0.96 ± 0.2 during autumn and winter seasons.So the highest population abundance was noticed in the summer season during the study period.This relationship between weather parameters and the seasonal population abundance of O. mangiferus, as increasing mean temperature stimulated the population increase of O. mangiferus.This finding was in line with Zaher and Osman (1970) found that population density of Oligonychus mangiferus increased gradually to reach its maximum density during warm and hot months of spring, summer.While relative humidity had a negative effect on their population, many studies had revealed that photoperiod length and temperature are closely related to phytophagous population increases (Fujimoto and Takafuji, 1986).Studies on Oligonychus sp.(Banks) life tables showed faster development of these mites as soon as temperature became higher (Wermelinger, 1990).On the other hand, the high humidity has a negative effect on the survival of the active stages of phytophagous mites, which tolerate 60-80 % R.H. (Perring et al., 1984).For the predator species Amblyseius swirskii, it was the most dominant species among predacious mites which infect mango trees.Abou-Awad et al. (1992) investigated the phytoseiid mite A. swirskii (Athias-Henriot) which was the most commonly encountered predator associated with this pest.Their mean abundance increased during summer and decreased during autumn in the first year but it disappeared in autumn in the second year of study.Results in Table (2) and Figure (2) stated that its highest mean abundance was recorded during summer (1.33 ± 0.05) and the lowest mean abundance was recorded in autumn (0.23 ± 0.09).In the second year, its highest mean abundance was 0.51 ± 0.1 during summer but it disappeared during autumn.Zaher and Osman (1970) found that Amblyseius hutu had two peaks in March and in September and October on mango leaves.These results are similar to Zaki (1992) who estimated that predaceous mites occur in moderate population throughout autumn and summer.El-Halawany (2001) found that the predatory mite A. swirskii had one annual peak in July.Mohamed and Nabil (2014) reported that the predator Amblyseius swirskii is the more abundant among other predaceous mites occur on mango trees.While Kandeel et al. (1986) estimated that this predator was the most dominant on citrus trees and feed on phytophagous mites and crawlers of scale insects.Finally, these phytophagous mites may regard as food supplementation to natural enemies has been shown to enhance conservation of predators in the crop and to increase the efficiency of pest control (Messelink al., 2014).This phytoseiid predatory mite, which has become a crucial tool in many integrated pest management strategies (Calvo et al., 2011).In conclusion, the result of the present study stated that air temperature and relative humidity had a significant effect on the increase or decrease of the phytophagous and predaceous mites.

Table ( 1): The seasonal mean abundance (± SE) of O. mangiferus and its predator A. swirskii associated with mango trees from October 2014 to September 2015. Table (2): The seasonal mean abundance (± SE) of O. mangiferus and its predator A. swirskii associated with mango trees from October 2015 to September 2016. Second year
The seasonal mean abundance (± SE) of O. mangiferus and its predator A. swirskii associated on mango trees from October 2015 to September 2016.
Fig.1.The seasonal mean abundance (± SE) of O. mangiferus and its predator A. swirskii associated on mango trees from October 2014 to September 2015.