Black tupelo (a.k.a. black gum, sour gum) (Nyssa sylvatica) is one of my favorite native trees. The straight species has horizontal branches sculpted into an attractive pyramidal canopy. Lustrous elliptical dark green leaves display a spectacular range of eye-popping colors in the fall, from orangish-yellow to deep red. The many cultivars offer variations on these themes.
Black tupelo needs no additional embellishments to be a standout tree, but adding frilled leaves trimmed in red elevates the ornamental value to a whole new level. Of course, I may be biased.
The frilled edges of the leaves are the handiwork of the so-called Tupelo Leaf Edge Gall Mite (Aceria dina, syn. Eriophyes dinus, Family Eriophyidae). The gall structure is striking with the thickened, puckered tissue rolling towards the center of the upper leaf surface.
The galls are light green and a bit ho-hum at first. However, when the frills turn red, they’re show stoppers! I’ve long contended that if we called the affected trees, Black tupelo ‘Eriofrillio', everyone would want one. I could be biased.
Of course, all eriophyid mites are not equal. It’s common for small, light green, bead-like bladder galls produced under the direction of the Tupelo Bladder Gall Mite (A nyssae (syn. E. nyssae)) to appear and spoil the aesthetics of the leaf edge galls.
The bladder galls appear randomly either singly or in clusters on the upper and lower leaf surfaces. They are not particularly attractive. Even I can’t be convinced that Black tupelo ‘Eriobladdero’ would be a must-have cultivar.
Obviously, I recognize the absurdity of naming a cultivar after the symptoms of a plant pest. No one can guarantee ‘Eriofrillio’ would remain true to form. Eriophyid mite populations including those that are gall-makers tend to rise and fall dramatically from year to year.
This speaks to the broader point that although the effects of eriophyid mites, in general, may be obvious, their impacts on the overall health of their host are seldom significant. This is particularly true of the two species of eriophyid gall-makers that occasionally appear on black tupelo. Indeed, I consider both to be somewhat rare.
The relatively harmless nature of the galls coupled with their rarity means the black tupelo eriophyid mites have not been the subject of any miticide efficacy trials that I can find. Adding to the challenge is that miticides effective against spider mites (family Tetranychidae) may not be effective against eriophyids. Of course, timing is another challenge with gall-making eriophyids because the galls may protect the mites from the effects of the miticides.
The bottom line is that I can cite no scientific evidence that the gall-making eriophyids on black tupelo can be chemically suppressed. Thus, my tongue-in-cheek unabashedly biased perspective is that if you can’t beat ‘em, appreciate ‘em. Signage may be helpful: Black Tupelo (Nyssa sylvatica ‘Eriofrillio').