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Abs tract. Linear equations for five pearl millet varieties were established for yield losses due to damage by the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera: Noctuidae), using a panicle damage rating scale. A very high positive correlation (r> 0.90; P = 0.001) was found between damage rating and percent yield loss, and also between observed and predicted yield loss. The low percent absolute deviation (% ad) and deviation ratios (dr) between observed and predicted yield loss demonstrated the reliability of the damage rating scale, and the established yield loss equations. In addition, the damage rating on farmers' fields by farmers and a team of technicians showed that the method can be used for quick on-farm assessment of yield loss by extension agents and farmers. In four farmer's fields, the estimated yield loss for the local variety (Sadore local) ranged from 11.7 to 41.9%. Implications in the use of the method in future crop loss assessment in pearl millet are presented and discussed.

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Life-fertility tables were described for Bracon hebetor Say (Hymenoptera: Braconidae) developing on the millet head caterpillar (MHC),Heliocheilus albipunctella de Joannis (Lepidoptera: Noctuidae). Mated B. hebetor females lived an average of 24.7 days, oviposited ca. 22 days, and produced 173.7 adult progeny with a 1:1 sex ratio. The estimated innate capacity of increase (r \ and net reproductive rate (R o ) were 0.26 and 86.5, respectively. The mean generation time wa.-. I days.

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Printed In Kenya All right\ rc\c.r\c.d * POPULATION DYNAMICS ~Zh'l) PjlKASI'I'ISM OF CONIESTA (=HAIMBACHIA) I(;IVEFLISALIS, SESAMIA CALAMISTIS, AN 1) HELIOCflEII,L~S Al~BIPb'~VC"l'E1,I.n IN M1lJl,'t;,'I' hlONOCl'1,l'liHE Abstract-Studie$ were conducted in Uigcr in 19x6 and 19x7 on the population dynamic* and parasitism of the millet \ t t m borer. ('oniu.!ftr (=lfaimhachia) igncl/usali.\ (Hampron) (1,epidoptera: l'yralidae), Se~amia ca1an1itti.s Ilampson, and the liiillet head caterpillirr, 11eliocheilus albipunctella de .loannir (I,epid~~pter:r:Soctuidac). I'lanting date\ were assessed for effects on population densities of C'. ignefi~.salis and ti. ~rlhiprrnctella. I'opulation dcnsitics of ('. igne/usalis were not reduced hy adjusting millet planting dater. I)ut were affected hy millet growth stage. Platytelenomus sp. (Hymenoptera: Scclionidae) was the mo$t common para~ite of ('. ignefu.so1i.s on millet. Parasitism of C'. ignefusalis larvae and pupae was rare. Se.wmia cnlamistis was a minor pest of millet i n Nigcr, and was rarely parasitimd. I'opulation dcndies oft!. alhiprrnctella were reduced by delaying millet planting dater. Rracott hebetor (Hjrnenoptera: f{rirconiduel was the most common parasite of H. alhipunctella. Hesum&-Des etudes etaient mences en 1986 et 1987 5ur la dynamique e l le parasitismc du foreur des tiges du mil. L'oniesra (= Haimhachia) ignefirsali.\ Olarnpson) (1.epidoptera: lJyralidae), de Sesamia calamistis Hampson, el de la mineuse de I'epi du mil,tfeliocheilus alhipunctella de Joannis (Lepidoptera: Nc~tuidae). 1,'influence des dates de semis *ur Ies densites des populations du foreur des tiges du mil, et de la mineuse de I'epi de mil a e t i evaluke. Ides denhiles des populations de C. ignefusalis n'etaient pas reduites par I'effet der changement des dates de semis, mais etaient affecteespar lestadededeveloppement du mil. Pla~vrel~nomus sp. (Hymenoptera: Sce1ionidae)etait le plus frequent parmi les paravites de C'. ignrfirsalis sur le mil. 1, e parasitisme des larves et chrysalides de C'. ignefusalis Plait rare. S. calamistis n'Ctait pas un important nuisible du mil au Niger, et etait rarement parasite. Les densites des populations de la mineuse de I'epi du mil etaient reduites en retardant les dates de semis du mil. Rracon hehetor Say (Hymenoptera: Rraconidae) etait le plus frequent parasite de la mineuse de I'kpi du mil.

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