An evaluation of five insecticides [chlorpyrifos, carbofuran, phorate, isofenphos, carabaryl] for the control of foliage and soil insects in a groundnut crop in Malawi and some effects of soil insects on yield parameters

• Main Authors: Wightman J.A, Wightman A.S
• Format: Book
• Language: English
• Published: 1988
• Subjects: aphis; arachis hypogaea; carbofuran; carbofurano; comejen; insecte nuisible; insecticidas; insecticide; insecticides; insectos daninos; malawi; pest insects; plant viruses; termite; termites; virus de las plantas; virus des vegetaux

Slow release formulations of phorate, carbofuran and chlorpyrifos (all at 2 kg/ha), isofenphos granules (2.5 kg/ha) and a drench of carbaryl (8 kg/ha in 1500 1 water/ha) were applied to and mixed into the soil of a field into which groundnut seed (cv. Mani Pintar) was subsequently sown. These treatments had no strong influence on crop yield. Aphid density and the incidence of groundnut rosette virus were reduced early in the season by carbaryl. Jassid density was slightly reduced by chlorpyrifos. Carbofuran slightly increased weevil density. Chlorpyrifos had a depressing effect on termite density. Macrotermes was most abundant in the plots treated by isofenphos, and least abundant where no insecticide was used. However, isofenphos lowered the millipede density. Millipedes were responsible for 77% of the 10-15% (bored) pods, most of the remainder having symptoms typical of white grub attack. The crop was sun dried as per the normal practice in Malawi. Only chlorpyrifos protected the haulms from depredations caused by termites.