Location: Subtropical Plant Pathology Research
2011 Annual Report
The intent of this study is to develop basic insect vector acquisition and transmission parameters for Squash vein yellowing virus (SqVYV), alone or in commonly observed mixed infections with Cucurbit leaf crumple virus (CuLCrV), Papaya ringspot virus (PRSV-W) and/or Cucurbit yellow stunting disorder virus (CYSDV). This information will be a key component of management strategies we develop as our preliminary data indicates that SqVYV is not efficiently transmitted by whiteflies and is not retained for more than a day. This year, we studied the effect of mixed infections of SqVYV with PRSV-W on the acquisition access period (AAP) of SqVYV by whiteflies and our results further support a semi-persistent mode of transmission with optimal AAP of 4 hours. Shorter or longer AAP reduced the transmission of SqVYV regardless of the infection status of the source plant. Additionally, we observed that SqVYV can be acquired as soon as two days after a plant is either mechanically or whitefly inoculated with SqVYV. During 2009 and 2010, natural whitefly populations were surveyed in a watermelon field to determine their distribution within a plant. Our results revealed a stratified distribution of the different life stages of whiteflies within watermelon plants, with eggs grouped on younger leaves within the first third of the main runner of the plant. Small nymphs were generally found in the second third of the main runner while large nymphs were found on the oldest leaves on the last third of the main runner. A similar pattern was observed on the secondary runners. Adult whitefly distribution followed egg distribution, suggesting that younger tissues in the watermelon plant are preferred for feeding and oviposition. Characterization of the within plant distribution of adult and immature whiteflies on watermelon will enable the development of more accurate sampling methods. For additional details see the report under the parent project 6618-220000-034-14R.
Progress was monitored via through direct involvement in lab and field activities, research meetings, telephone calls and email communications.