Vol. 16—1962 - NorthEastern Weed Science Society

424
PLANTRESFONSETO T~IZONE
E. G. Terrell, Jr.
SOIL Fu~I~,N7
Weed control in forest tree nurseries continues to be a high
labor cost operation despite the general use since 1948 of
petroleun distillate or oil sprays. (2,S). In the Northeast,
weed control is complicated by the great variety of species
grown for reforestation. Some are tolerant while others are
sensitive or intolerant. Seedlings of Scotch pine and larch,
while ordinarily not killed by moderate amounts of oil spray
applied during the first year, are often damaged so that
plantable-size seedlings are not produced Ul 2 years. Hardwood
seedlings, which are intolerant to oil spray must be handweeded
or cultivated.
Weed control in seedbeds is most important during the first
year when the small, relatively slow-growing seedlings are
least able to stand the competition of fast-growing weeds.
Hand-weeding is costly, and may do considerable damage if
weeds are allowed to get large. The use of soil surface
herbicides, such as Neburon. before or soon after tree seed
germination causes high seedling mortality in some species.
Weed control need not be considered sep~ately from the control
of other nursery pests if one treatment will provide effective
control of both. Soil funigants. ~~hich erradicate or greatly
reduce the numbers of living weed seeds and weed vegetative
parts, as well as nematodes. fungi, and insects. are useful
nursery tools. They can help the nurseryman get the seedlings
past the first critical year with a minimum of damage by pests.
Soil funigation is not new; in fact. it has been in use since
World War I left large stocks of Chloropicrin (4). Funigation
with methyl bromide under hand-sealed plastic tarps has become
standard practice in some Southern nurseries. but adoption of
the practice in the Northeast has been slow. Labor costs,
soil temperatures. sowing times. and tIle severity of the
damage by weeds and pests in the Northeast are quite different
from those in the South.
The development of a tractor-mounted combination injector-tarp
layer by the DowChemical Co. led to our resumption of funigant
testing in 1959 (1,6). Results obtained from an application of
one of the test materials, Trizone. is reported here.
l
1 Manager. Saratoga Tree Nursery. N. Y. State Conservation
Department, Saratoga Springs, N. Y.