Velvet blight disease on pepper caused by a mutualistic symbiosis relationship between a fungus, Septobasidium and a scale insect, Pinnaspis. The disease was reported for the first time in Transau, Sanggau Ledo and Entekong (Bengkayang and Sambas District), West Kalimantan at 1989. The symptom of velvet appeared mostly on berries and petiole of the leaves. It seemed to be harmless, and it was considered as a minor disease to the pepper vines, so the farmers leaved it over. The farmers were more focused on controlling foot rot disease, as the major constraint of pepper production. However, since 2009 the velvet blight disease has been spreading on many pepper gardens, especially in Bengkayang and Sambas. The disease was estimated to cover about 5.37% of the total production area. The fungus attacks the stems, branches, petioles, leaves, spikes and berries of pepper vines. The fungus forms a brown fungal mat that grows on the infected plant parts and cover the plant completely at advance stage. The infected branches fail to produce new leaves and berries and finally the infected plant dies slowly. The dispersal of the disease may be occurred through planting material and wind mainly. At the end of 2014, the disease severity covered about 17.09% of the total pepper production area of West Kalimantan. Nowadays, the velvet blight disease has been found in East Kalimantan, Bangka-Belitung, Lampung, South and Southeast Sulawesi province, but still in low intensity; However, the precaution by eradicating the infected parts have to be carried out to minimize more severe damage in the future.
Early symptom of Velvet blight disease. (A) Pepper vine with mild disease; (B) Active development of mycelia of Septobasidium on twig; (C) Infected petioles; (D) Infected berries, and (E) Infected the main stem
Advanced symptom of Velvet blight disease. (A) The severely infected plant. Advanced infected on: (B) Twig; (C) Branches and main stem; (D) Petioles; (E) & (F) Petioles and leaves; and (G) Berries
Death vines caused by velvet blight disease at Bengkayang, West Kalimantan (A) Dead vines amongst the diseased vines, and (B) A dead vine adjacent to the healthy vines.
The velvet blight disease
This disease was first named as Septobasidium blight in 1970 by the researcher from Sarawak (Kueh Tiong Kheng), and then referred as Velvet blight in 1972 based on the visible disease symptoms. In the early stage of the disease, the color of the fungal mat is grey and then turns chocolate brown. It grows on the branches, twigs, petioles, leaves, spikes and berries. The fungal mat may cover the infected plant parts completely. The infected berries may survive to maturity, but the pericarps of the infected berries are difficult to be removed even after soaking it in the process to produce white pepper.
Septobasidium fungus. (A) Running mycelia on the branches; (B) Running mycelia & pillar structure (→); (C) Tip of the pillar structure; (D) The fungal mat and the pilars form labirin, and (E) A basidium.
Little information is available on this disease of black pepper worldwide. The disease is a kind of mutualistic symbiotic interaction between a Septobasidium fungus and Hemiptera insect, Pinnaspis. Three species of Pinnaspis have been reported associate with the fungus in India and Malaysia. In Indonesia, the species of the Pinnaspis is not identified yet, as well as the species of the Septobasidium.
The Septobasidium acts as plant pathogenic fungus, It obtains nutrient from the host by parasitising, getting substances secreted by the insect (Pinnaspis), and also benefitting from fungal propaguls dispersal that attach to the body of the insect. The insect gets protected from harsh environment because of the houses of fungal mat.
Pinnaspis scale insect associates with Septobasidium fungus. (A) A nymph of Pinnaspis (red →) and the fungal pillars (→); (B) Imago of Pinnaspis (→) (after the fungal mat removed), (C) Nymph under microscope (D) Further stage of the nymph (ventral view), and (E) Imago (dorsal view).
Other plants affected: Rubber; Jack-fruit; Rambutan; Nutmeg
Control suggestion:
- Use healthy planting materials maintain the garden properly
- Monitoring pepper vines regularly to detect the presence of the disease
- Prune and destroy the infected plant parts
- Fungicide application (with tebuconazole or copper as an active ingredient reported effectively control the disease) or a systemic insecticide.
Written by:
Dyah Manohara dan Dono Wahyuno
Indonesian Spice and Medicinal Crops Research Institute (ISMCRI) Indonesian Agency for Agricultural Research and Development (IAARD)
Jalan Tentara Pelajar No. 3 Bogor, Indonesia 16111
dyah_manohara@yahoo.com