Everglades Station Mimeo Report 56-11
CONTROL OF "HEAD WOOL" IN DITCHES
Dalton S. Harrison
Assistant Agricultural Engineer
The aquatic weed Najas guadalupensis commonly known as "Head Wool", can
be effectively controlled by the use of certain emulsifiable solvents. This weed
grows well in alkaline water and is reproduced by seed and root stock. Treatment
by applying the solvents is very cheap and fast as compared to dragging or cleaning
with a dragline.
Some of the more commonly used solvents for underwater treatment of "Head
Wool" are: (1) 63% gasoline and 37% Polychlorobenzene with 22%a Triton X-155 or
Monsanto-L emulsifier, (2) 74% Drip oil and 26% Polychlorobenzene with 21% emulsi-
fier or, (3) 84% AiSCO Solvent "B" and 13% Polychlorobenzene with 2 / emulsifier.
The control of "Head Wool" depends on the use of these chemically active solvents,
primarily aromatic and some other unsaturated hydrocarbons.
For ordinary farm laterals, treatment can be made by injecting the blend-
ed solvents underneath the surface of the water every 50 to 200 feet, depending on
the degree of infestation. The solvents should be blended to a specific gravity of
1.01 to 1.03 and added to the ditch at about 40 ppm. Subsequent treatments of
20 ppm may not be needed from one to two years after initial treatment. Laterals
on sandy soils require about 80 ppm for initial cleanout. After initial treatment
the ditch should not be disturbed for at least 72 hours. After this, normal pump-
ing in or out may be resumed. Carbon dioxide or nitrogen should be used rather
than a gear pump when the flash point of the solvents is below 800F. A pressure of
40 psi is sufficient to break up the particles with underwater application.
EXAMPLE TO FIGURE TREATMENT NECESSARY
(1) Lateral: 2640 ft. long, 4 ft. wide, 4 ft, deep.
(2) Multiply 2640 x 4 x 1.x 7,5 (gal. per 6u. ft. of water)- ,316,8QQ gals. of,
a 'later in ditch,
(3) Multiply the total number gallons of water in the ditch to the desired treat-
ment (40 ppm); 316,800 x 40 = 12,672,000.
(4) Divide this figure (12,672,000) by 1,000,000 = 12.67 gals. material needed.
(5) Using: 65% gasoline 0.65 x 12.67 = 8.2 gals. gasoline
35% Polychlorobenzene 0.35 x 12.67 = 4.4 gals. PCB
2p% emulsifier 0.025 x 12.67 = 0.3 gal, emulsifier
(6) Material Costs: Gasoline .(8.2 gals. x $ .25) = $2,05
PCB (4.4 gals. x 01.65) = $8.25
Emulsifier (0.3 gal. x $4.25) = $1.27
Total $10.57 S
May 17, 1956