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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #112011
Title: TRANSMISSION AND THE ROLE OF HONEYBEES IN FIELD SPREAD OF BLUEBERRY SHOCK ILARVIRUS

Author
item BRISTOW, P - WASHINGTON STATE UNIV
item Martin, Robert

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Blueberry shock ilarvirus (BlShV) particles were detected on and in pollen collected from diseased bushes. The virus was only transmitted to trap plants during the bloom period suggesting involvement of pollen in the transmission. When flowers were removed from the trap plants the rate of transmission was decreased but not eliminated. The virus was readily transmitted to potted trap plants when a hive of honeybees was placed in cages covering infected field bushes and the trap plants. Some transmission occurred even when there was no hive in the cage. Survival of infected pollen in hives is very limited as the transmission of virus from hives to plants was very inefficient. Within the first week of taking hives from a cage containing infected field plants, there was no transmission in the second week after removal of the hive from source plants. BlShV is mainly spread by foraging honeybees that become contaminated with pollen containing BSIV while visiting flowers on infecte bushes and then depositing it on flowers of healthy plants. There was no transmission when thrips were introduced into cages containing healthy trap plants and a source of infected pollen. The virus spreads rapidly once introduced into a planting.

Technical Abstract: Particles of blueberry shock ilarvirus (BSIV) were detected on, in, and between the four cells of the blueberry microspore (pollen tetrad). Healthy potted trap plants only became infected when placed in fields with infected bushes during bloom. Removing flowers from trap plants before they were placed in the field reduced, but did not eliminate transmission. BSIV was readily transmitted to potted trap plants when a hive of honeybee was placed in cages covering infected field bushes and the trap plants. Some transmission occurred even when there was no hive in the cage. Trap plants remained healthy when they were caged with healthy field plants either with or without hives. Infective pollen does not appear to survive within the hive as there was no spread to trap plants when hives, taken from fields with infected plants, were placed directly into cages with only trap plants. Blueberry shock ilarvirus is mainly spread by foraging honeybees that become contaminated with pollen containing BSIV while visiting flowers on infected bushes and then depositing it on flowers of healthy plants. There was no transmission when thrips were introduced into cages containing healthy trap plants and a source of infected pollen. The virus spreads rapidly once introduced into a planting. The pattern of spread within a block of a given cultivar appears to be random. Spread between adjacent blocks planted to different cultivars, however, does not appear to be random. All 42 cultivars tested were susceptible to BSIV when inoculated by grafting.