Palatability and efficacy to possums and rats of pest control baits containing bird repellents

Repellents used to reduce by-kill of birds during pest control must not compromise acceptance by target species. Two repellents combined, anthraquinone (AQ; 0.4 g kg^?1) and d-pulegone (DP; 1.0) did not reduce the palatability of blue-coloured carrot baits to laboratory rats (Rattus norvegicus); nor did DP (2.0). Green-coloured carrot baits coated with AQ, DP or AQ + DP were taken from bait stations by wild possums (Trichosurus vulpecula) and rats. Toxic (1080) bait coated with AQ (0.4) and peanut oil (0.1) had reduced palatability but was accepted by laboratory rats. However, laboratory rats did not consume enough baits coated with AQ and bacon, peanut butter, cinnamon or DP to be killed. Anthraquinone (0.4 or 0.8) plus cinnamon and DP (0.5) did not affect palatability or lethality to captive ship rats (R. rattus) or possums. Anthraquinone and DP as surface coatings on baits are therefore acceptable to possums and possibly rats, at concentrations that deter some bird species.     

Oligouronide signaling of proteinase inhibitor genes in plants: structure-activity relationships of Di- and trigalacturonic acids and their derivatives.

Polygalacturonic acid (DPave approximately 20), alpha-1,4-di- and trigalacturonic acids, delta 4,5-alpha-1,4-di- and delta 4,5-alpha-trigalacturonic acids, and several chemically modified derivatives of these oligomers were prepared. Their proteinase inhibitor-inducing activities were determined by supplying solutions of the compounds to young, excised tomato plants through their cut stems. Digalacturonic acid, on a molar basis, was the most active oligomer (ED50 approximately 1.5 micrograms/plant), being about three times more active than the parent oligogalacturonic acid (ED50 approximately 5.5 micrograms/plant). The specific inducing activity of trigalacturonic acid was about half that of digalacturonic acid. Both delta 4,5-di- and delta 4,5-trigalacturonic acids were about half as active as di- and trigalacturonic acids, respectively. Reduction of the hemiacetal (carbonyl) group of the di- and trigalacturonic acids with sodium borohydride completely destroyed proteinase inhibitor inducing activities, indicating that the inducing activity of both acids depends upon an intact hemiacetal at the reducing termini. Reduction of the double bonds of delta 4,5-di- and delta 4,5-trigalacturonic acids by catalytic hydrogenation with H2 (palladium catalyst) produced derivatives with specific inducing activities of approximately one-half that of the parent compounds. Thus, while the reducing termini of oligogalacturonides require an intact hemiacetal for proteinase inhibitor inducing activities, the nonreducing termini of the small oligouronides do not require a C4 hydroxyl nor a C5 proton to be active inducers.