Greenhouse and field experiments were conducted to evaluate clopyralid formulations and triclopyr ester alone and in mixtures for control of honey mesquite. In the greenhouse the butoxyethyl ester of triclopyr enhanced activity of the monoethanolamine salt of clopyralid when applied as mixtures for total rates of 210 to 630 g ae ha-1. Greenhouse activity of triclopyr was not enhanced with the addition of clopyralid. In the field, 1989 applications of these same formulations, mixtures, and rates were usually synergistic, with each mixture killing more plants than the combined effect of either herbicide applied alone. For example, clopyralid plus triclopyr at 140 plus 140 g ae ha-1 killed 87% of the plants. When applied alone at 140 g ha-1 neither herbicide killed >27% of the plants. Honey mesquite response to the potassium or oleylamine salt of clopyralid was similar to the monoethanolamine salt when applied alone or in mixtures with triclopyr ester. Effectiveness of these mixtures in 1990 was similar to the 1988 and 1989 applications except that two to three times more herbicide was required for high mortality in 1990 because of unfavorable environment and plant growth prior to treatment.

Field evaluation showed oxydemeton methyl 25% E.C. at 0.6 kg a.i./ha and dimethoate 40% E.C. at 0.74 kg a.i./ha to be more effective than cypermethrin 40% E.C. at 0.25 kg a.i./ha, decamethrin 2.5% E.C. at 0.03 kg a.i./ha, endosulphan 35% E.C. at 0.8 kg a.i./ha and profenofos 50% E.C. at 0.74 a.i./ha in the control of apterae on potatoes. Disulfoton 10G at 1.6 k0g a.i./ha and carbofuran 10G at 5.2 kg a.i./ha were superior to oxamyl 10G at 5.2 kg a.i./ha and terbufos 5G at 2.6 kg a.i./ha applied in the furrow at planting for the control of aphids. Although these insecticides gave good control of apterae, the alate population in the treated plots varied from significant reduction to no reduction. All the insecticides tested did not significantly increase potato yield, although mean yields were increased.