Controlled release insecticides

The acyl groups introduced included 4-phenylbenzoyl, phenylacetyl, 4-methoxybenzoyl, acetyl, 2,4-dichlorophenoxyacetyl, and 2,2-dichloropro-pionyl. Introduction of the last pair of acyl groups is important because they are bioactive (insecticides), i.e., the product can be employed in controlled-release formulations [159]. The structures of all these esters were determined by FTIR and NMR spectroscopy, whereas their solution properties, includ-... 

Nelson, J.H., D.L. Stonebumer, E.S. Evans, Jr., N.E. Pennington, and M.V. Meisch. 1976. Diatom diversity as a function of insecticidal treatment with a controlled-release formulation of chlorpyrifos. Bull. Environ. Contam. Toxicol. 15 630-634. 

Polymeric oxazolines have also been used as vehicles for controlled drug release ° ° and DNA transfection, as polymeric micelles, which serve as carriers for drug transport (e.g., paclitaxel), and as formulation additives for controlled-release of insecticides. ... 

The most intensive effort to use pheromones in insect management has been in Australia, where an attract-and-kill strategy has been developed for protecting stone fruit crops. Historically, the Oriental fruit moth, Grapholita molesta Busck, was the major stone fruit pest, and heavy insecticide applications kept both this moth and, coincidentally, the Carpophilus beetles at acceptable levels. However, the widespread adoption of pheromone-based mating disruption for G. molesta control released the Carpophilus beetles from insecticide pressure, and these beetles, Ca. davidsoni in particular, became the dominant stone fruit pests (James et al., 1994). Late applications of broad-spectrum insecticides often... 

The main use of PVC is for intravenous bags. However, PVC has been used in the controlled release of volatile insecticides, herbicides, pheromones, and perfumes by diffusion through a PVC membrane of multilaminated stripes. A monolithic matrix device of PVC can be prepared by mixing PVC particles with a suitable plasticizer and an active agent, followed by heating of the mixture in a mold. A solid PVC matrix is obtained from the subsequent cooling. 

Another area of concern is the residual life of a pesticide once it is brought back to the hive. Microencapsulated methyl parathion was at one time believed to represent a special hazard because of its controlled release feature. Thus methyl parathion from MMP was reported to persist in stored pollen for up to 17 months.( ) Unfortunately, little is known about the persistence of insecticides in honey bee combs etnd the subsequent effects of their residues on the honey bees. Carbaryl has been shown to persist for at least eight months in colonies ( ) euid permethrln for at least seven months.O) Recently, USDA researchers at the University of Wisconsin studied samples from two bee kills that apparently Involved methomyl and MMP applied to sweet com. Samples were collected to determine, among others, whether methomyl persisted in combs. Analysis demonstrated that eight months after the insecticide application, residues of 0.03 ppm of methyl parathion and 0.03 ppm of methomyl ( 5) remained, even though the latter is considered to be a short-residual pesticide. 

A Comparison of Pheromone, Pheromone and Pyrethrold and Insecticides for Control of the Pink Bollworm In the Imperial Valley, CA." USDA, 1981, Butler G. D. and Barker R. J. Klassen, W. Rldgway, R. L. Inscoe, M., In "Insect Suppression With Controlled Release Pheromone Systems" Kydonleus,... 

Drugs are applied topically primarily for local effects however, this route can be used to administer drugs for systemic action. Few drugs readily penetrate intact skin. The absorption of drugs that do penetrate the skin is proportional to the surface area over which they are applied and to their lipid solubility. Increased cutaneous blood flow also enhances absorption. Systemic toxicity can become evident when highly lipid-soluble substances (e.g. lipid-soluble insecticides) are absorbed through the skin. Controlled-release patches are now commonly used in human medicine for transcutaneous drug administration. 

Similarly, we would expect that an adsorbed solute could be desorbed by washing the carbon with an appropriate solvent. The behavior can be envisioned as though the carbon were acting as a reservoir for the gradual and controlled release of the adsorbed substance—a concept that has been considered for various applications. As mentioned earlier, years ago carbon was employed as a carrier of medicinals to be released for ailments in the gastrointestinal tract. More recently, it has been used to safen the action of fungicides and insecticides on sensitive foliage. 

Controlled-release solid formulations of selected volatile organophosphorus pesticides (malathion, DDVP, sumithion, chlorpyriphos, and sulprofos) were studied by Szente [33]. These solid formulations exhibited negligible vapor pressure and preserved their entrapped pesticide content even at elevated temperature. Malathion and chlorpyriphos formulations showed increased physical stability, and resulted in an effective masking of the unpleasant smell while the complex formulations existed as dry solid. Sulfluramid is an expensive insecticide that is lost by volatilization, but complexation to j8-CyD reduced the loss [21]. 

Some patents refer to the controlled release of certain pesticides [58, 59]. Matolcsi et al. [60] used j8-CyD to prepare inclusion compounds with benzenesul-fonylurea derivatives with herbicidal or plant growth regulator properties [61], obtaining a prolonged controlled release of the active ingredient. Ikeuchi et al. [62] prepared inclusion complexes of triazole derivatives which presented potent insecticidal activities at low concentrations for an extended period. 

A different strategy for controlled release is based on polymer permeability other than degradation. The active reagent may be encapsulated within a polymeric membrane or in a strip, as shown in Figure 5.53. Ideally the reagent is contained in the reservoir as a saturated solution with excess in suspension. This allows diffusion through the membrane at constant rate without loss of activity. Alternatively, the reagent may be dispersed in a polymer matrix and released to the environment by diffusion or extraction. A variety of membrane and matrix devices are commercially available [99]. Pheromone release strips for insect control and household fly and cockroach strips for release of insecticide are also in commercial use. 

Scher, H.B. Development of herbicide and insecticide microcapsule formulations. In Proceedings of International Symposium on Controlled Release of Bioactive Materials, 1985, pp. 110-111. 

Degradable materials also offer new perspectives in agriculture (e.g., the controlled release of fertilisers, insecticides and herbicides)... 

Geotextiles have a large variety of uses. These can be used for mulch around newly planted seedlings (Figure 7.9). The mats provide the benefits of natural mulch in addition, controlled-release fertilizers, repellents, insecticides, and herbicides can be added to the mats as needed. Research results on the combination of mulch and pesticides in agronomic crops have been promising. 

In other agricultural aspects, it has been shown that relevant agricultural substances, such as insecticides, can be incorporated into PHA granules. If spread in the environment, PHA-degrading bacteria can slowly degrade the PHA granule, leading to controlled release of the insecticide. This pioneer idea was proposed for the first time by Holmes (1985) and was recently supported by Philip et al. (2007). 

Since these polymers slowly decompose in water, it has been proposed that acid components with biological action should be chosen so as to obtain herbicides, insecticides, etc. for controlled release of biological action. 

Dr. B.R. Ambedkar National Institute of Technology -Jalandhar. Seven students have completed their Ph.D. degree under his supervision. He has a wide experience in the field of natural products, polymers composites, hydrogels, removal of toxic heavy metal ions from waste water, removal of colloidal particles, sustained drug delivery, controlled release of insecticides/pesticides, etc. He has more than 80 research papers in various reputed international journals. He has more than 60 research papers in the proceedings of the international conferences and... 

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