Agriculture Reference
In-Depth Information
Wettable powders are easy to store, transport, and handle, but are hazard-
ous to the applicator, particularly in mixing where the concentrated dust may
be inhaled; however, they are usually not, absorbed through the skin as readily
as emulsifiable concentrates.
Many of the insecticides sold for garden use are in the form of wettable
powders because there is very little chance that this formulation will burn fo-
liage, even at high concentrations. In contrast, the original carrier in emulsifi-
able concentrates is usually an aromatic solvent, which in relatively moderate
concentrations can cause foliage burning at temperatures above 32.5ºC (90ºF).
Wettable powders can be used with most types of application equipment.
As long as the suspension is adequately maintained, they will not clog noz-
zles, provided strainers and nozzle screens are sufficiently large. WPs are abra-
sive, however, and may cause both pumps and nozzles to wear more quickly.
3.
Water-Soluble Powders or Soluble Powders
In water-soluble powders or soluble powders (WSP or SP), the technical
grade material is a finely ground, water-soluble solid and may contain a small
amount of wetting agent to assist its solution in water. It is simply added to
the spray tank, where it dissolves immediately. Unlike the wettable powders
and flowables, these formulations do not require constant agitation. They
form true solutions and form no precipitate. Because of their sometimes dusty
quality, soluble powders may be packaged in convenient, water-soluble bags
which are simply dropped into the spray tank. Examples of these are the ni-
cosulfuron herbicide Accent
®
SP and the linuron herbicide Lorox
®
SP.
4.
Water-Soluble Bags
Some wettable and soluble powders are sold in water-soluble bags or
packs (WSB or WSP). These products are formulated in a soluble package so
that the inner bag is placed directly in the spray tank and subsequently dis-
solves. This type of packaging eliminates the need for measuring and mini-
mizes your risk of exposure. Examples of this packaging are Pounce
WSB,
Ammo
WSB, and Brigade
WSB, all of which are products of the FMC
Corporation.
5.
Water-Soluble Concentrates, Liquids or Solutions
The active ingredient in water-soluble liquids or concentrates (S, WS,
WSC or WSL) is soluble in water and is formulated either with water or with
a solvent, such as alcohol, which mixes readily with water. When added to
water in the spray tank, WSCs form a true solution and require no further agi-
