Figure 3. Evaluation of in vivo preventative and therapeutic effects of HWY-4213 against PWN in pot-grown pine trees.
(A) The nematicidal effect of HWY-4213 formulated as a trunk-injection agent was evaluated using the in vitro HTS assay. (B) The in vivo preventative activity of HWY-4213 in trunk-injection formula was examined using 4 year old pot-grown pine trees. In this experiment, pine trees were incubated for 2 weeks after receiving different doses (10 pine trees/dose) of one of the testing compounds: HWY-4213 only, HWY-4213 in trunk-injection formula or morantel tartrate in trunk-injection formula. After this 2-week pretreatment, the trees were inoculated with B. xylophilus (10,000 nematodes/mL) and maintained in pots for 2 months, during which their growth status was observed. Trees that died were cut into pieces and observed for the presence of B. xylophilus. (C) The in vivo therapeutic activity of HWY-4213 in trunk-injection formula was measured at a single dose of 50 g/m3. Ten pine trees were first inoculated with B. xylophilus (10,000 nematodes/mL) and then incubated for 2 weeks. Thereafter, each PWN-infected tree received a single injection of each drug (50 g/m3) and was maintained in the pot for 2 months, during which the dead trees were observed. To confirm that dead trees were infected with PWN, they were cut into pieces and examined for the presence of B. xylophilus.