Dynamics of Polymyxa graminis and Indian peanut clump virus (IPCV) infection on various monocotyledonous crops and groundnut during the rainy season

Abstract

The progress of Indian peanut clump virus (Hyderabad isolate; IPCV-H) and its vector Polymyxa graminis in various monocotyledonous crops and groundnut was studied during the 1994, 1995 and 1996 rainy seasons in a naturally infested field in India. The roles of rainfall and temperature in the dynamics of infection by both the virus and its vector were analysed by exposing young seedlings for short periods in the field. Of the host crops studied, wheat, followed by barley, showed the highest virus incidence, although P. graminis was rarely observed in roots of wheat and was not detected in those of barley. The roots of maize, pearl millet and sorghum plants infected by P. graminis showed intense colonization by sporosori. IPCV accumulated in systemically infected maize plants; the sorghum and pearl millet cultivars studied showed a transient presence of IPCV-H. Rice was seldom infected by the virus and P. graminis was not detected in its roots. Groundnut was a systemic host for the virus, although during these experiments no P. graminis was found in its roots. Groundnut appeared to be susceptible to infection, mostly in the early stages of crop development, and the rate of IPCV-H transmission in groundnut seeds was highest (13%) for plants infected when young. The seedtransmission rate quickly decreased in plants showing symptoms 1 month after sowing. Time of infection had little influence on groundnut pod yield, which was always reduced by >60% in infected plants. There was some evidence that the quantity and distribution of rainfall influenced the incidences of IPCV-H and P. graminis : high rainfall resulted in high incidences of the virus and P. graminis , and a weekly rainfall of 14 mm was sufficient for P. graminis to initiate infection. Temperatures prevailing during the rainy season ranged from 23 to 30 ° C and were found to be conducive to natural virus transmission. These results suggest measures to be explored for controlling peanut clump disease.

Diseases of Edible Oilseed Crops

“…Peanut clump disease is known to cause losses exceeding U.S. $40 million to peanut alone on a global scale. The virus has also been shown to infect a range of monocotyledonous plants, which include wheat, barley, maize, sorghum, foxtail millet, pearl millet, and various grassy weeds (Delfosse et al 2002). In addition to peanut, the virus has the potential to cause crop losses at least in sugarcane, wheat, barley, maize, sorghum, chillies, and Bambara groundnut.…”

“…There is some evidence that quantity and distribution of rainfall influences the incidences of IPCV-H and P. graminis; that is, high rainfall with temperatures ranging from 23°C to 30°C results in high incidences of the virus and P. graminis, and a weekly rainfall of 14 mm is sufficient enough for P. graminis to initiate infection for natural virus transmission (Delfosse et al 2002).…”

Genetic Management of Virus Diseases in Peanut

“…Below 23°C, infection is suppressed and fungal development is delayed (Legreve et al 1998). The virus replicates well over the same range of temperature as the fungus, but temperature~ higher than 30°C are not favorable to the virus (Delfosse et al 2002). The virus is transmitted through peanut seed (6%-50%) and also through seeds of finger millet (Eleusine coracana), fox tail millet (Setaria italica), pearl millet, maize, and wheat (Triticum aestivum).…”

Targeting highly conserved 3′-untranslated region of pecluviruses for sensitive broad-spectrum detection and quantitation by RT-PCR and assessment of phylogenetic relationships

“…Both viruses are carried by the obligate parasitic protist Polymyxa graminis. They are found on cereals such as sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum), maize (Zea mays) and sugarcane (Saccharum officinarum), and can also affect bread wheat (Triticum aestivum) (Delfosse et al, 2002).…”