Host choice experiment
One potted knotweed plant of each species was placed into a rearing cage
equidistant from each other in a randomly assigned position in each
cage. Each cage was randomly assigned to receive one of four psyllid
treatments (Hokkaido, Kyushu, F2 FemKYU, or F2 FemHOK), with six
replicate cages set up for each treatment for a total of 24 cages. Using
a manual aspirator, 25 females and 25 males about 14 days old of the
corresponding psyllid population were collected in a 33 mL polystyrene
vial and then released at the center of the cage. The inoculation period
for this experiment was 72 hours, after which all adult psyllids were
removed from the cage. The knotweed plants were also removed, and the
number of eggs on each plant was counted by visually inspecting the
surface of the leaves using a 10x magnification hand lens. Once the eggs
were counted each plant was covered individually by a mesh cage (1 m
tall x 40 cm wide) that was secured to the rim of the pot by an elastic
band and labeled with the treatment and replication number. Individually
covered plants were placed in the greenhouse (21 °C ± 5, RH 50% ± 10,
16L: 8D) where knotweeds were grown. After 50 days the number of emerged
adults from each plant was recorded.