Pseudaulacaspis pentagona (Targioni Tozzetti)
Common name: White peach scale, mulberry scale.
Geographical distribution: This cosmopolitan pest is common in warmer regions, and in greenhouses in colder regions. CIE Map #58, 1996 (revised).
Morphology: The body of the female is pyriform and its short, dorsal macroducts are two-barred, arranged in transverse rows. The large median lobes are joined at their bases (“zygotic”), the second pair of lobes are much smaller, bilobed, and the third lobes are very small but sclerotized. The perivulvar pores, about 60-80 in two groups, occur in five clusters on either side of the anus. The fifth cluster, of about 10-25 pores, is situated above the anus, which is located between the anterior group of pores. The prosoma is devoid of gland ducts. The female shield is white, almost round, with the darker, dorsal juvenile exuvia at one end. The elongated shield of the male is whitish, its exuvium is at the apex.
Life cycle: This scale is unique among armored scale insects in that it initially lays pink-colored female eggs, then yellow-white male eggs. Fecundity depends on the host and the temperature. About 75 eggs/female were produced when it was reared on potatoes, only 45 on peach seedlings; most progeny were produced at 25ºC. The calculated threshold of development is around 10ºC. The pest infests all above-ground parts of treess. In the mountainous regions of Turkey the scales has two annual generations, in summer and in the fall; along the coastal plain it has three, during April, mid-summer and in the fall.
Economic importance: This scale is the main pest of peaches in eastern Turkey, especially along the coastal plain, and a serious pest in kiwifruits in Northern Greece. In heavy infestations the entire trunk may become white, due to the color of the shields. Branches or even entire trees, especially the more susceptible younger ones, can die, sometimes years after the infestation. At times the scale is controlled by natural enemies, but pollution in urban areas, and pesticide applications in rural regions, reduce their effect. This results in severe damage to ornamental plants in towns and cities. The pest may also cause major problems in areas where it was accidentally introduced without its natural enemies.
Monitoring: Pheromone traps are used for detecting the pest in newly infested regions. Yellow sticky traps are used for monitoring male emergence, and to capture the crawlers. The optimum time for spraying would be 2-5 days after peak captures. Traps should be set up as soon as eggs begin to hatch in the spring, and are to be examined daily or every other day, in order to determine the peak in emergence.
Horticultural methods: The forced removal of scales from heavily infested trees, either manually or by intensive water sprays, can reduce the pest population and improve the efficacy of pesticides. The surrounding vegetation, which may be a source of pest re-infestation, is to be periodically examined.
Chemical control: White oils, organophosphates and insect growth regulators(IGRs), applied when most of the scale population consists of the vulnerable crawlers, may control the pest. However the organophosphates often interfere with and curtail the activities of the natural enemies.
Biological control: In different parts of the world the pest is attacked by many parasitoids and predators, which control this scale, provided they are not killed by pesticides. In eastern Turkey its main parasitoid is the aphelinid endoparasitoid Encarsia berlesei (Howard), which may kill up to 40% of the scales. Another aphelinid, the ectoparasitoid Aphytis sp., caused much pest mortality in north-eastern Egypt. Several predators, including Chilocorus bipustulatus (L.) (Coccinellidae) and Cybocephalus fodori minor (Endrody-Younga) (Cybocephalidae) also contribute to scale control.
Erkiliç, L. and Uygun, N. 1995 Distribution, population fluctuations and natural enemies of the white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzettini) (Homoptera: Disspididae) in the east Mediterranean region of Turkey. Israel Journal of Entomology 29: 191-198.
Erkiliç, L.B. and Uygun, N. 1997. Development time and fecundity of the white peach scale, Pseudaulacaspis pentagona, in Turkey. Phytoparasitica 25: 9-16.
Erkiliç, L.B. and Uygun, N. 1997. Studies on the effects of some pesticides on white peach scale, Pseudaulacaspis pentagona (Targ.-Tozz.) (Homoptera: Diaspidae) and its side-effects on two common scale insect predators. Crop Protection 16: 69-72.
Kreiter, P. and Panis, A. 1998. Inventory of the natural enemies of the white peach scale Pseudaulacaspis pentagona (Targioni-Tozzetti,1886) in the world (Homoptera, Diaspididae). Bulletin de la Société Entomologique de France 103: 263-271.
Kreiter, P., Thaon, M., Dijoux, L. and Giuge, L. 2006. La cochenille blanche du mûrier sur pêcher. Essais d’utilisation de pièges à phéromones en vergers de pêchers pour détecter Pseudaulacaspis pentagona. Phytoma la Défense des Végétaux: 28-31.
Paloukis, S.S., Navrozidis, E.I. and Kukuryanis, V.H. 1997. Contribution to the integrated control of Pseudaulacaspis pentagona Targ.-Toz. (Homoptera: Diaspididae) on kiwifruit trees (Actinidia chinensis). Acta Horticulturae 444: 797-802.
Saber, F.M.M., Rawheia, H.R. and Sahar, A.A. 2010. Seasonal fluctuation of the white peach scale insect, Pseudulacaspis pentagona (Targioni) and its associated parasitoid, Aphytis sp. at Mett-Ghamer, Dakahlyia. Governorate, Egypt. Egyptian Academic Journal of Biological Science 8: 1-9.
Sheble, D.A.F. and Kozár, F. 1995. Use of colour traps for monitoring Pseudaulacaspis pentagona (Homoptera, Coccoidea) and its parasitoid Encarsia berlesei (Hymenoptera, Aphelinidae). Acta Phytopathologica et Entomologica Hungarica 46: 273-277.