Demand-Driven Technologies for Sustainable Maize ... - IITA

263Table 3. S. calamistis larval arrest on eight maize genotypes.GenotypesS5 9-1S5 11-1S5 27-1S5 27-3Tzmi 103Tzi 4001S5 20-2Tzmi 407MaizegenotypesS5 9-1S5 11-1S5 27-1S5 27-3Tzmi 103Tzi 4001S5 20-2Tzmi 407Number of fi rstinstar arrested2.8 ± 0.8 a4.6 ± 1.8 a7.6 ± 3.8 a2.2 ± 1.1 a5.6 ± 1.8 a7.2 ± 2.9 a7.2 ± 1.1 a6.6 ± 1.9 aMean ± s.e.larvae/plantrecovered 10days afterinfestation*1.3 ± 0.5 b3.3 ± 1.3 b5.5 ± 0.8 b4.1 ± 1.8 b1.1 ± 0.4 b3.5 ± 1.8 b20.2 ± 2.9 a4.2 ± 1.2 bLarval recovery (Mean ± s.e.)*% of third instararrestedNumber of borers recoveredat harvest timeTotal021-030-80 ± 00 a65 ± 15 a86 ± 05 a90 ± 10 a95 ± 05 a75 ± 05 a86 ± 05 a86 ± 05 a% oflarvae01000-000-% ofpupae00100-01000-% of third instarentering the stem*Means within a column followed by the same letter are not significantly different (P>0.05, LSD)Table 4. S. calamistis larval establishment on eight maize genotypes.Mean % ofstem tunnellingatharvest time011.429.6-017.210.4-*Means within a column followed by the same letter are not significantly different (P>0.05, LSD)Larval arrestThere were no signifi cant differences among genotypes for fi rst instarlarval recovery (Table 3). In general, the percentages of fi rst instarlarvae recovered were very low for all the eight maize genotypes. Incontrast, the percentages of third instar larvae recovered were veryhigh (>60%) for all the genotypes. There were no signifi cant genotypicdifferences in the third instar larvae recovered. However, 5% of theselarvae were already established inside the stem of the two susceptiblegenotypes (S5 20-2 and Tzmi 407) two days after the infestation(Table 3), while 5% of those recovered on the resistant S5 9-1 causedno damage to their host plants after the same period of time.Larval establishmentA highly signifi cant number of larvae per plant were recovered tendays after infestation from the susceptible S5 20-2 but not fromthe resistant S5 9-1 (20 vs. 1.3 larvae/plant) (Table 4). Signifi cantdifferences were also observed between the susceptible S5 20-2 andthe others in terms of the number of larvae that had settled down tendays after infestation (Table 4). At harvest time, very few borers were00005055