Coccids - pests of apple.
A survey of collections containiing over 1400 species, the pertinent literature and quarantine records covering the past 30 years in the USSR established that apple in some 70 countries throughout the world is infested by 100 species of coccids in 55 genera and 6 families. Most of the injurious species, including Quadraspidiotus perniciosus (Comst.), Pseudaulacaspis pentagona (Targ.), Pseudococcus comstocki (Kuw.), Lepidosaphes ulmi (L.) and Parlatoria oleae (Colv.), are polyphagous and infest many food-plants. Those limited to pip fruits or other rosaceous plants include Nilotaspis halli (Green), Epidiaspis leperii (Sign.), Melanaspis inopinata (Leon.) and Parlatoreopsis pyri (Marl.). Two that are restricted to apple are Parlatoria destructor Newst. in Australia and Dentachionaspis centripetalis Rao in India. Further lists are given of the most widely distributed species, which include some of those already mentioned and various others. The danger of the acclimatisation of fresh species in the USSR is slight, but some that infest apple are known as pests of greenhouse and house plants, such as Aspidiotus nerii Bch. (hederae auct.) and Russelaspis pustulans (Ckll.). The introduction of P. destructor from Australia constitutes a risk.Of 32 insects against which quarantine regulations are in force in the USSR, 12 are coccids, and 7 of these infest apple, the most dangerous being Parlatoreopsis chinensis (Marl.), Diaspidiotus ancylus (Putn.) and Neopinnaspis harperi McKenzie, which do not as yet occur there. The first infests 22 species of plants in China, the second is widely distributed in Canada and the USA and known in Spain, Portugal and the German Federal and Democratic Republics, and the third originated in the Far East and has spread to the USA (California and Florida). In all, 60 species of coccids infest fruit trees in the USSR, and 25 of them occur on apple. The most important on apple are Phenacoccus aceris (Sign.), L. ulmi and Q. ostreaeformis (Curt.) in the northern and non-black-soil areas, Q. perniciosus, Q. pyri (Licht.) and E. leperii in the south, Parlatoria oleae, Q. perniciosus, Lopholeucaspis japonica (Ckll.), Ceroplastes japonicus Green and Pseudaulacaspis pentagona in western Transcaucasia and Parlatoria oleae, Q. perniciosus, Eulecanium rugulosum (Arkh.) and Q. almaatensis (Borkhs.) in Central Asia. Further species are recorded from the Far East. Q. perniciosus is by far the most dangerous.