[□ | □] □
[□=□ | □] □
[!□ | □] □
Following an incubation period , the phytoplasma is transferred to healthy plants during leafhopper feeding . Plants that do poorly if cut back in the fall include ornamental grasses , such as blue oat grass and switch grass . If growth is normal , however , apply a low-phosphorous fertilizer , such as a lawn fertilizer containing no herbicide , at the rate of 1 ounce of actual nitrogen per year of tree age , not to exceed 16 ounces . Japanese beetles , Popillia japonica , are an introduced species .