From the Directors Desk: The Latest on New York State's Top Six Insect Threats

By Fred Breglia

With winter’s cold wind and plum­met­ing tem­per­a­tures, some days are best spent sit­ting inside learn­ing the lat­est about New York State’s inva­sive insects.

The top six threats are the Asian Long­horned Bee­tle, Emer­ald Ash Bor­er, Gyp­sy Moth, Hem­lock Wool­ly Adel­gid, Sirex Wood­wasp, and Vibur­num Leaf Bee­tle. Though the Vibur­num Leaf Bee­tle and Gyp­sy Moth are found at Lan­dis, thank­ful­ly none of the oth­er inva­sives have been dis­cov­ered. That being said, sev­er­al have been found in neigh­bor­ing coun­ties and we are mon­i­tor­ing the col­lec­tions, gar­dens, and grounds for signs of infestation.

  • The Emer­ald Ash Bor­er (EAB), Agrilus pla­nipen­nis, was first dis­cov­ered in south­east­ern Michi­gan in 2002 and in NY in 2009. This bee­tle infests and kills ash trees includ­ing green, white, black and blue ash. The lar­vae tun­nels under the bark, dis­rupt­ing the flow of nutri­ents and water, and effec­tive­ly gir­dles the tree. A large area in Albany Coun­ty has been quar­an­tined, with most infes­ta­tions locat­ed in the town of Beth­le­hem. Detec­tion has also occurred in Liv­ingstonville, south of Mid­dle­burgh, and in Syra­cuse. The NYS Depart­ment of Envi­ron­ment Con­ser­va­tion hung mon­i­tor­ing traps at Lan­dis, but for­tu­nate­ly no EABs have yet been caught. Dur­ing the win­ter, the EAB hiber­nates in pupae form. Research sug­gests tem­per­a­tures below freez­ing kill some of these insects before hatch­ing. The releas­ing of a stin­g­less wasp, EAB’s main preda­tor in Asia, is a con­trol tech­nique being test­ed as it kills both eggs and lar­vae. The goal is to estab­lish wasp pop­u­la­tions that can even­tu­al­ly bring EAB pop­u­la­tion num­bers down to a sus­tain­able level.
  • Anoth­er inva­sive is the Sirex Wood­wasp, Sirex noc­tilio, a native to Eura­sia that has caused major dam­age in the South­ern Hemi­sphere, includ­ing Aus­tralia and South Africa. As the female lays an egg under the bark, she secrets a tox­ic mucus and sym­bi­ot­ic fun­gus. The mucus cre­ates a suit­able envi­ron­ment for the fun­gus, which in turn decays the wood, mak­ing it eas­i­er for the lar­va to digest. The lar­vae then tun­nel deep into the trunks, weak­en­ing and some­times killing the trees. First dis­cov­ered in the US in Otsego Coun­ty in 2004, the great­est dam­age is seen in plan­ta­tions of Scotch, Aus­tri­an, and red pine. A par­a­sitic nema­tode, Delade­nus siri­cidi­co­la, which infects the wood­wasp lar­vae and ulti­mate­ly ster­il­izes the adult females, has been used for con­trol. Oth­er preda­tors include birds such as the swal­low­tail and black spot­ted woodpecker.
  • The Hem­lock Wool­ly Adel­gid, Adelges tsug­ae, was first dis­cov­ered in the Hud­son Val­ley in the 1980’s and has since spread through­out the State. It is relat­ed to aphids and is native to parts of Asia. This pest uses its long mouth parts to extract sap and nutri­ents from hem­lock foliage, caus­ing nee­dles to dis­col­or from deep green to gray­ish green and drop pre­ma­ture­ly. The loss of new shoots and nee­dles impairs tree health and is usu­al­ly fatal after sev­er­al years. Val­ued plant­i­ngs of the East­ern hem­lock could be rav­aged by the adel­gid, and the nat­ur­al stands of hem­lock in forests and parks would be great­ly affect­ed. This is espe­cial­ly true at Lan­dis where many acres of hem­lock thrive, includ­ing about 20 acres of old growth hem­lock. New attempts to con­trol the pest involve the release of ben­e­fi­cial bee­tles native to the Pacif­ic North­west that eat noth­ing but adel­gids. Sys­temic insec­tides have also proven to be some­what effective.
  • The Asian Long­horned Bee­tle (ALB), Anoplopho­ra glabripen­nis, is a species native to east­ern Chi­na, Japan, and Korea. It was dis­cov­ered in south­ern NY in 1996. No new infes­ta­tions have been detect­ed since 2007, and all have been in New York City and Long Island. Most of these infes­ta­tions were erad­i­cat­ed in 2013, though pop­u­la­tions still remain in Queens, Brook­lyn, and Ami­tyville. The ALB prefers maples includ­ing red, sil­ver, and sug­ar maples. It does most dam­age in the fall dur­ing its lar­vae stage. The lar­vae chew tun­nels through the wood to the tree’s heart, where they over­win­ter as pupae. Ear­ly detec­tion and burn­ing trees on site have been the best con­trols of this insect, which is able to fly one mile in search of a new food source.
  • The Vibur­num Leaf Bee­tle (VLB), Pyrrhal­ta viburni (Paykull), is a non-native that first appeared in NY along Lake Ontario in 1996 and has steadi­ly spread. Detec­tions have been made in almost every coun­ty includ­ing Schoharie. It is a vora­cious eater that can defo­li­ate vibur­num shrubs entire­ly. The insect over­win­ters in its egg stage, then hatch­es out in spring and feeds on the new­ly formed leaves, stress­ing the plant. After the crawlers leave, the adult bee­tle comes back to con­sume what­ev­er remains. Plants may die after two or three years. Luck­i­ly, sev­er­al gen­er­al­ist preda­tors feed on VLB lar­vae includ­ing lady bee­tle adults and lar­vae, lacewing lar­vae, and spined sol­dier bug nymphs and adults.
  • The Gyp­sy Moth, Lyman­tria dis­par dis­par, intro­duced in Maine in 1869, has spread through­out the North­east. Egg mass­es are found on tree branch­es and trunks. In the spring, the lar­vae dis­perse by hang­ing from silk threads that are car­ried by the wind. The lar­vae pre­fer eat­ing oak leaves, but will feed on over 300 species of trees and shrubs, cre­at­ing mas­sive defo­li­a­tion. Since females will lay eggs on dead wood, fire­wood is com­mon­ly a means of trans­port, so there is a reg­u­la­tion in NY that lim­its the trans­porta­tion of untreat­ed fire­wood to less than 50 miles from its source. Pre­da­tion by some bee­tles and the white-foot­ed mouse is an impor­tant fac­tor in pop­u­la­tion con­trol, as well as heavy rain­fall dur­ing the lar­val stage.

If you believe you have spot­ted any of these inva­sives, it is best to con­tact the NYS DEC at www​.ny​.dec​.gov for more assis­tance. You can also con­tact me for more insight on any of these pests.

Winter 2016

Volume 34 , Number 1

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