Potato Leafhopper in Abundance

July 06, 2000

Note the yellowish margins and curled/cupped foliage on this shoot damaged by potato leafhopper.

Potato leafhoppers (PLH) are prevalent in most Massachusetts orchards as of early July. Evidence of their injury is significant on foliage in young trees, as noted by yellowing margins and curled leaves of shoot growth (left). In general, they are of no concern in mature orchards, but I get pretty excited when I see them in young trees because they stunt new terminal growth. A severe PLH infestation can seriously stunt terminal shoot growth in young trees, hence impacting profitability. (An important point in orchard profitability is to get young trees growing and bearing as soon as possible, especially on dwarf rootstocks.) PLH has also been implicated in fire blight spread, so this year in particular would be a good year to keep them in check.

The recommendation is to treat young blocks with an effective insecticide -- Imidan, Guthion, Sevin, Thiodan, or Provado all work -- as soon as PLH or their injury are evident.Thidoan or Provado have more residual activity, and are probably the best choice. Again, it is generally not necessary to treat older trees, but do scout your young plantings for evidence of PLH and treat as necessary.

Left unchecked, potato leafhopper can seriously stunt shoot growth in young trees

Yellow margins of 'Honeycrisp' leaves do not necessarily indicate potato leafhopper injury -- it seems to be a characteristic of the cultivar.

Note: It has been widely observed that 'Honeycrisp' foliage exhibits yellowing of leaf margins similar to PLH injury. At first it was believed this was indeed PLH injury, but now it's thought that the yellowing is an inherent characteristic of the cultivar. Do scout your 'Honeycrisp' blocks for actual signs of adults or nymphs before treating.

For more information on PLH, see:

Potato Leafhopper, from West Virgina University's Kearneysville Tree Fruit Research and Education Center