Development of Photoactivated Compounds as Pesticides

Abstract

Although light has been known to enhance certain toxic reactions since 1888, the principle was not exploited until after 1970 to any great extent. The greatest concentration of effort has been in the study of photodynamically active dyes, primarily the halogenated fluorescein series, as prospective insecticides. More recently, compounds of plant origin have been isolated, identified, and studied as phototoxins against a wide range of pests, including insects, fungi, and weeds. The main classes studied to this time are the furanocoumarins, thiophenes, acetylenes, extended quinones, and the chlorophyll a intermediates popularized as "laser herbicides." It is apparent that this area of research will expand in the coming years rather than retrench.The expenditure of energy frequently helps to enhance the probability of successfully reaching one's goals in this universe. For as long as chemistry has existed as a science, we have input energy, most frequently heat energy, into chemical reactions to make the molecules or to produce the effects which we wanted. The use of light energy has remained quantitatively a minor component as a means of energy input. This has also been the case with the development of the pesticide industry. Light energy has not been used to drive toxicological reactions or to provide specificity for those reactions to any great extent until the decade of the 70's. Several review chapters have been written covering individual aspects of photodynamically active pesticides (1-8). The purpose of this chapter is to provide a chronological treatment of the development of light as an integral part of the toxicological action of several classes of pesticides; and also, to show the development of the various classes of light activated pesticides relative to each other.

Symposium-in-Print Porphyrins and Related Compounds as Photoactivatable Insecticides. 3. Laboratory and Field Studies

“…A considerable body of data has so far been accumulated regarding the potential of photodynamic sensitizers (i.e. near-UV-or visible light-absorbing polycyclic dyes that require the presence of oxygen (1) in order to exert their photosensitizing effect in biological systems) to act as phototoxins against a variety of noxious insects (2,3). Notable successes have been obtained by employing several classes of compounds, such as thione derivatives of natural or synthetic coumarins, thiophenes, furanochromones and xanthenes (4).…”

Multivariate statistical analysis of mid‐infrared spectra for the online monitoring of 2‐ethylhexyl acrylate/styrene emulsion copolymerization

“…Phloxine B (C 20 H 2 Br 4 Cl 4 Na 2 , MM = 829.7) is one of a range of xanthene derivatives that have been intensively studied as photoinsecticides 32, 33. The light‐dependent insecticidal activity of Phloxine B alone or combined with uranine or spinosad (CAS No.…”

Impacts of UV radiation and photomodification on the toxicity of pahs to the higher plant Lemna gibba (duckweed

“…If a chemical is photoactive (because it either is a photosensitizer or is photomodified to a more toxic species), solar radiation has the potential to increase its hazards. Because many pollutants [31], as well as pesticides [32], are photochemically active, this could be a common mode o f action. Moreover, many photoactive chemicals are structurally modified by light as they move through the environment, so the loads of the chemicals should be based on the parent compounds and their associated derivatives.…”