gall disease on leaves of blackboard tree (alstonia scholaris) infected with pathogens ..

gall disease abnormal development outgrowth host plant tissue irritation bacteria fungi insects cause tumor leaves stems crown blackberry rose crown cedar apple leaf fungus aphid mite wasp flies majority blackboard tree alstonia scholaris tender twigs gallinaceous pauropsylla tuberculate crawford seasonal occurrence pathogen temperature psyllid psyllidae jumping plant lice infect bug hemiptera flowering herbivorous fauna secrete lerp green