Evaluation Of Intercropping for the Management Of The Stem Borer Coniesta ignefusalis Hampson and The Head Miner Heliocheilus albipunctella de Joannis in Different Varieties Of Pearl Millet In The Nigerian Sudan Savanna
*B. M. Sastawa1 and N.E.S. Lale1, 2
1Department of Crop Protection, Faculty of Agriculture, University of Maiduguri, P. M B. 1069, Maiduguri, Nigeria. 2Current address: Department of Animal and Environmental Biology, Faculty of Science, University of Port Harcourt, Port Harcourt, Nigeria.
Accepted in January 2004
Two field trials were conducted in 1997 and 1998 cropping seasons in Maiduguri, northeastern, Nigeria, to assess damage by the stem borer Coniesta ignefusalis and the head miner Heliocheilus albipunctella in Ex-borno, Zongori, Wame, Gargasori, Mboderi and GB8735 millet varieties sown as sole crops and also as intercrops with cowpea (cv. Borno brown) or sorghum (cv. Gooseneck). Damage in Ex-borno arranged in a row with cowpea or sorghum in cropping patterns of 3:1, 2:1, 1:1 and 1:0 was also assessed. Both trials were sown on July 14. The stem borer caused significantly lower damage (number of emergence holes and larval tunnels) in sole millet and higher damage in millet intercrops in 1997. Mboderi in 1997 and Ex-borno in 1998 suffered significantly more tunnelling from the borer than the other varieties; in contrast, GB8735 suffered the lowest damage in 1997. Gargasori, sown as sole crop or as intercrop, was not infested by head miners in 1997. However, significantly higher numbers of head miner larvae infested sole Ex-borno in the same year. Grain yields were significantly higher in Zongori than in the other varieties in both 1997 and 1998; yields were lowest in GB8735 intercropped with cowpea in both years. The stem borer caused significantly higher damage to millet in the 1:1 pattern in 1997 and in the 2:1 pattern in 1998. Similarly, the head miner caused significantly higher damage to millet in the 3:1 pattern in 1998. Grain yields were significantly higher in 1:0 and lower in 1:1 patterns in both 1997 and 1998. Grain yields in the millet-cowpea were significantly higher in 1997 and lower in 1998 than in the millet- sorghum intercrop system.