Pesticidal formulations are divided into various delivery systems. Examples are water-soluble liquids, emulsifiable concentrates, wettable powders, flowable suspensions, and dispersible granules. These formulations are individually developed for a specific pesticide compound and must be easily diluted and sprayed by the applicator. Often, field tank mixing of multiple pesticide formulations or pesticide formulations in liquid fertilizers is performed to broaden efficacy and reduce application costs. Physical and chemical incompatibility sometimes occurs with these mixtures, causing activity loss, uneven spraying, and nozzle clogging. Compatibility problems can frequently be avoided by using clean equipment, pretesting the mixture in a small jar, and adding one of the many commercially available compatibility agents to the spray tank. Pesticide mixtures that have inadvertently developed problems in the field can sometimes be rejuvenated by chemical and spray equipment adjustments. Applicators are reminded that strict adherence to product label statements for tank mixing is mandated by the U.S. Environmental Protection Agency.

Annotation The proceedings of a symposium in San Antonio, Texas, November 1991. The 22 papers discuss the use of pesticides, in sections on safety and environmental impacts, characteristics of formulations and adjuvants, and application techniques and pest control. For engineers and chemists. Member price, $34. Annotation copyrighted by Book News, Inc., Portland, OR.

The routine use of pesticide tank mixtures has increased the importance of formulation tank mix compatibility. Unfortunately, compatibility is very sensitive to the mixing and spraying conditions. Consequently, incompatibility occurs erratically in the field and is difficult to consistently reproduce in the laboratory. While compatibility in the field can never be totally predicted in the laboratory, the test method used in this work provides good predictions, while still allowing the testing of many combinations of pesticides and carriers with a reasonable effort.

Liquid fertilizers can vary in pH, free ammonia content, viscosity, salt concentration, nutrient analysis, and water activity. Most pesticides are complex organic molecules and are formulated in such different forms as wettable powders, flowables, emulsifiable concentrates, and solutions. Reaction from combining the two can result in anything from a uniform mixture to the formation of substances resembling gels, thick creams, or oily scum which may settle on the bottom of the tank, float on the top, or coat the insides of the tank and spraying equipment. Spraying such incompatible mixtures can result in uneven distribution, poor performance, crop injury, and the buildup of soil and crop residues. A wide variety of compatibility agents is being offered to growers to improve the performance of their chemicals. These compatibility agents differ widely in their chemistry as well as in their performance. A simple test using proportionate quantities of the components can provide growers and custom applicators with the compatibility potential of their chemicals and will also aid in determining whether or not a particular compatibility agent would alleviate the compatibility problem. The results of various liquid fertilizer-pesticide compatibility tests will be discussed. Standard procedures will be offered for performing a compatibility test. Guidelines for premixing various pesticide formulations and compatibility agents before adding them to the spray tank have been established.

Fhosphrus-based anionic surface-active agento and their role in agrochemical formulation; seed tretment formulation; development of a protocol; evaluation of factors affcting tank mix compatibility of pesticide combinations; a metho for emulsion aptimization through computerized regression ;a small-scale system to evatuate anti-foam performance; mitial studies on.the effects of droplet size and eletrostatics on spray deposition efficoncie; efficacy of insecticida applied ultra-low volume in vegetable oils; use of electrostaties, rotary atomizers and vegetable oils in low-volume ground appication; control of spruce budworm by ultra-low-volume application of an isecticide suspension