Vol. 11 No. 1 (1999): Buletin Hama dan Penyakit Tanaman
Geminivirus infecting pepper: symptom variation and transmission study Infection of geminiviruses has been reported to cause signz3cantyield loss on various crops. Polymerase chain reaction was able to detect geminivirus infection on pepper samples around Bogor and Cipanas, West Java. Symptom variation and transmission of the geminivirus infectingpepper was studied using five solanaceae plants with three dzgerent transmission mannec i.e. mechanical inoculation, side grafirng, and insect vector. The transmission study showed that mechanical inoculation was not able to transmit the eminivirus, while side grafting and insect vector, Bemisia tabaci, caused infection with symptoms varies from yellow mosaic, leaf curl leaf distortion, to stunting of the plant. Higher infection was observed on pepper var. Hot Chilli through B. tabaci (8009) and side grafting (71.4%) than those on chilli pepper and tomato. DNA fiagment of - 1.7 kb was amplified wing PCRfim those plants showing symptoms, but no DNA fiagment was observedfrom symptomless eggplant and tobacco var. White Burley. Thus it can be concluded that the last two kina3 ofplants were resistant to the geminivirus infectingpepper.
A farmer survey, to determine the way potato farmers perceived the leafininer fly and methods they employed to control the pest, was conducted in ten highland vegetable production centers in five provinces jhm June to September 1998. The total number of potato farmers interviewed was 309. The study revealed that the farmers were familiar with the leafininer as a new pest that have caused heavy damage since 3-6 years ago. However, only few farmers (5.5%) were knowledgeable that L. huidobrensis was an exotic pest. Most farmers (>75%) reported that leafininer infestation caused more than 40% yield losses, and the crops have to be harvested 2-4 weeks earlier than was the nomal practice. All respondents applied insecticides to control the leafininer twice a week. Insecticides mostly used were pyrethmids and organophosphates. Selection of pesticides was based on farmer's own experiences, other farmers experiences, and based on suggestion jhm pesticide kiosk's owners. Although insecticides were used intensively, most farmers (72%) were dissatisfied with the efficacy of control. Biological control with parasitoids may pegom satisfatorily only if it B accompanied by minimizing insecticide use.
Morphological Variation of the Asian Honeybee Apis cerana (F.) (Hymenoptera: Apidae) in West Java. The diversity of Asian honeybee Apis cerana (F.) (Hymenoptera: Apidae) occupying low and high altitude habitats in West Java was studied using morphological analysis, based on the length of proboscis, hindleg, front wing, tergites, and sternites. All morphological characters measured were signifcantly longer in high altitude bees compareded to those of low altitude bees (p < 0.05), except proboscis. Dendogram analysis showed that bees from those two altitudes were separated, whereas the result of principal component analysis indicated that both belong to the same group (P < 0.05).
Selection of Coconut Resistance to the Nutfall Disease (Phytophthorapalmivora Butler) The objective of this research was to select the coconut resistance to nutfall phytophthora disease. Using wounding inoculation method, detachedhits of 11 coconut populations at Pakuwon Coconut Cropping Pattern Research Station were inoculated with Phytophthora palmivora Co5 isolate. Based on the dhease lesion size at seven days after inoculation, Genjah Salak (GSK) coconutpopulation was more resistant than the other coconutpopulations and showed individual resistance variation to the disease. From 238 GSK coconut trees selected, 226 (95%) trees were resistant and 12 (5%) trees were susceptible.