Vol. 51—1997 - NorthEastern Weed Science Society

104
estern New York Nursery IPM Program:
1995-1996 Weed Scouting Results
J. C. Neal, C. A. Casey, and K. E. Dean l
In 1995 and 1996 three production nurseries, two container nurseries and one field nursery, in
Erie Coun , NY were scouted for weeds as part of a Nursery IPM program. The methods used were
adapted fr m those developed by Dr. Andrew Senesac in the Long Island Nursery Weed IPM
Scouting P ogram and involved an inventory of weeds present in each nursery block, and
subsequen y highlighting the more prevalent and / or important species in each block. The scouting
blocks wer defined by the grower's field designations and differed between sites. While each
nursery ha its own unique weed spectrum, several similarities were observed between container
nurseries a d between one container nursery and the field nursery.
At site , a container nursery producing a variety of woody shrubs, the weeds encountered were
fairly typi I of this type of nursery with the most prevalent being wind-dispersed, seed-propagated
species inc uding hairy galinsoga, fireweed, (Erechtites hieracifoliai, and horseweed. Other species
encounter included creeping woodsorrel, bittercress, dandelion, annual bluegrass, common
chickweed Virginia copperleaf, and an aster (unidentified). There was a clear relationship between
the impo nee of weed species in pots with prevalence in the areas surrounding the pots. Also, pots
carried ov r from the previous year had more weeds than newly potted plants.
Contai r nursery 2 had some of the same and many different species. The most prevalent
species inc uded common groundsel, nodding beggarticks, field violet (Viola arvensis), ragweed,
wild buc heat, hairy galinsoga, smartweed (Polygonum caespitosum), and occasional pots with
quackgras , mugwort and yellow nutsedge. At this nursery the newly potted plants had more weeds
than did p ts carried over from the previous season and weed prevalence in adjacent areas was not a
good predi tor of weed species dominance in the pots. These observations plus evaluation of the
potting me ia components and a quick scouting of the field production areas on that nursery
suggested hat weed propagules were introduced with the field-grown liners which were potted.
The on field production nursery which was scouted had a greater diversity of weed species but
had severa weed species in common with the second container site (additionally supporting the
suggestion that container nursery 2' s weeds were introduced with the field-grown liners). Weed
spectrum i each block differed with the type of production but several species were common in
each field ncluding field yellowcress (Rorippa sylvestris) and field violet, two species which until
recently h d not been common in the region. Other species encountered in all blocks included
yellow nu edge, horseweed, Powell's amaranth, dandelion and pineappleweed. Blocks differed
with respe t to other important species. For example: one block was extensively infested with
mugwort, ith lesser amounts of yellow nutsedge, goldenrod and western salsify. Another block
had wides read infestations of hairy nightshade and spotty infestations of quackgrass. A particularly
notable sp cies occurring in sporadic patches was bermudagrass. Factors which appear to have
influence the species infesting each field included field history, the amount of cultivation relied
upon for eed control, and (probably) introduction of weeds with planting stock.
These ta showed that late summer scouting adequately inventoried the weeds in each nursery,
demonstr ed the diversity of weeds within and between nurseries in this region, emphasized the
need for r gular weed scouting in all nursery blocks, and suggested the potential role of planting
stock in t movement of weed propagules within and between nurseries.
1 Assoc. Pr f., NC State Univ., Raleigh, NC; IPM Specialist, Dept. Flor. & Om. Hort., Cornell Univ., Ithaca, NY;
and Extn. gent, Cornell Coop. Extn. of Erie Co., East Aurora, NY, respectively.