Vol. 15—1961 - NorthEastern Weed Science Society

556.
pick~rel spawning suacess but this occurred in neighboring lak~s
where nothing v-as done to t the habitat.
;)0JJ1l:,1AHY AND CONCLUSIONS
1. In recent years, at least a fourth of th~ area of Lak~
~op~tcong had been rendered useless for boating, swimming and fishing
b~cause of heavy infestations of milfoil, MyrioEhyllum spicatum.
2. A combination of winter drawdown to freeze the exposed
plants, and application of 2,4-D granules has effectively controlled
chis plant. Preuent observations suggest that this control will
08 adequate for at least two seasons.
3. Tape grass, Vallisneria americana, has succeeded much
uf the milfoil, and may reach nuisance proportions. The fact that
this condition is much more localized and occurs only during the
latter part of the summer makes this a problem of much less magnitude
than that presented by milfoil.
4. Pondweeds did not increase during the past year and the
0vidence suggests that they will continue to be at least as abundant
as in the past. To date this infestation has not reached serious
proportions.
5. Present evidence suggests the possibility of phenol
contamination from the use of at least some of the commercially
produced 2,4-D granules. This problem warrants further study.
RECOMMENDATIONS
1. A winter drawdown of Lake hopatcong to a depth of eight
feet is recommended for 1960-61 in an attempt to control the tape
grass. Additional drawdowns will be -r-econm ended whe!ll1necessary.
2. Herbicidal control of the more dense growths of t ape grass
and pondweed should be attenpted. This will reqUire some additional
-f'Le Ld testing wi th chemicals which. appear to have a greater herbicida:}.
effect on these plants than does the 2,4-D granules.
3. Spring and fall surveys should be continued to keep abreast
of changes in composition and distribution of the rooted aquatics.
This will enable us to plan for the next season's weed control program
and evaluate the results of current operations.