The geographical Distribution of Mealybug Wilt with Notes on some other Insect Pests of Pineapple.
AbstractIn the course of a survey in 1937-38 for natural enemies of Pseudococcus brevipes[Dysmicoccus brevipes], Ckll., information was obtained on the geographical distribution of the mealybug wilt that it causes in pineapple. The distribution of the wilt is reviewed from the literature, including unpublished references to its occurrence in Florida, the Loochoo Islands, the Bonin Islands and some of the Japanese Mandated Islands. It was found by the author in South Africa, Kenya Colony, Malaya, the Philippines, Australia and Fiji, but not in Java, though the mealybug was present there. The incidence of the wilt was low on virgin lands rich in organic matter and in areas of high rainfall without extreme temperatures. The mealybug was found wherever pineapple was growing and caused green spotting [cf. R.A.E., A 21 64] in many localities; these green-spotting strains, however, appeared to have different symbionts from those of the corresponding strain in Hawaii, and it no longer appears likely that the rod-shaped symbiont, typical of the latter, is the cause of this symptom [of. 23 166]. The possibility that different biological strains of P. brevipes have developed is discussed [cf. 26 570 etc.]. There was no evidence of effective biological control of P. brevipes, with the possible exception of a single case of fungous infection in Queensland.
A list is given of other mealybugs found on pineapple, of which only P. adonidum, L., which produced well-defined chlorotic spots on pineapple leaves in Queensland, appeared to affect the plant. Occasional infestations by a Diaspine scale were found in Africa and in Fiji, where it produced large chlorotic spots on the leaves, and Oryctes monoceros, 01., and Anomocaulus fulvovestitus, Fairm., were observed causing serious though localized damage in the heart tissues of young plants in Portuguese East Africa and Fiji, respectively.