or enter directly through the respiratory system and leave no residue in or on the
product. Because of this, the commodity is subject to immediate reinfestation.
Fumigation should only be used when other methods of control are ineffective or where
thorough penetration is required. It is to control various pests in stored subsistence,
rodent burrows, wooden structures, and soil.
e. Dusting. This is the application of pesticides in the form of solid particles
extending in size over the same range as liquids. Dusts are classified as being less
than 400 microns in diameter. Dusts provide good residuals, remain airborne a long
time, and provide good penetration. One of the biggest problems with dusts is drift
since they do not adhere well to surfaces and can be blown away by the first wind.
Dusts are effective against crawling insects, in ectoparasite control, and in and around
f. Granules and Pellets. Granules and pellets possess many characteristics of
dusts except that they are greater than 400 microns in diameter; are subject to little or
no drift; and can be effectively dispersed by air because of their excellent vertical
penetration. Granules may be used in aquatic habitants for mosquito larvae control, in
areas inaccessible to wheeled vehicles, and where repeated treatment is not desirable
g. Miscellaneous. Many miscellaneous dispersal methods (such as painting,
swabbing, dragging, and baiting) are also available. These applications are fairly
specific will not be discussed here.