000 04613nam a22004697a 4500
001 G70456
003 MX-TxCIM
005 20211006084810.0
008 121211s ||||f| 0 p|p||0|| |
020 _a92-9146-065-6
040 _aMX-TxCIM
072 0 _aF03
072 0 _aH60
090 _aCIS-2674
100 1 _aKanampiu, F.K.
_uMaize Production Technology for the Future: Challenges and Opportunities. Proceedings of the Eastern and Southern Africa Regional Maize Conference, 6; Addis Ababa (Ethiopia); 21-25 Sep 1998
110 2 _aCentro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico)
245 0 0 _aAdvantages of seed-primed imazapyr for Striga hermonthica control on maize bearing target-site resistances
260 _aAddis Ababa (Ethiopia)
_bCIMMYT|EARO :
_c1999
300 _ap. 172-179
340 _aPrinted
520 _aSeed treatments (a drench after planting, hard and powder coats, as well as priming and planting wet and dry) were tested as cost effective procedures for preventing Striga (witchweed) damage, even in the most heavily infested soils. The use of maize mutants with acetolactate synthase target site resistances available should allow application of the high levels of herbicide needed to effect season-long control. Various salts of imazapyr, a herbicide previously shown to have the least phytotoxicity and the longest persistence, were tested in screenhouse experiments and the magnesium salt proved optimal and was used for most of the field experiments. Two field experiments, one each during the long rains (March-July) and short rains (October- January) were initiated at Kibos in Kenya to determine the optimal formulation and methodology of seed dressing for effective Striga hermonthica control on two maize hybrids with different ALS target site resistances. Seeds were dressed with various rates of magnesium imazapyr and planted when either wet or dry. These treatments were compared with the conventional method of post emergence application, and with drench- dressing of seed in each planting hole with a herbicide solution. Maize seeds treated with imazapyr and planted wet, resulted in significantly reduced plant stand 6 weeks after planting when compared to other treatments, but only during the long rains. Emerged Striga on untreated maize increased from 6 to 12 weeks after planting and started to fall thereafter as maize roots begin to die. There was hardly any Striga emergence for three months after planting on with primed maize seeds even at very low doses. The few Striga plants that emerged and flowered by 12 weeks after planting formed no seed by harvest during both seasons. During the short rains, all treatments except for the controls and hills with 15 g a.i./ha imazapyr application had less than one Striga stalk with flowers and capsules per m2 at 12 weeks after planting. Striga was almost completely suppressed when seed was coated with 30 and 45 g a.i. imazapyr/ha in a commercial fungicide-insecticide seed dust or polyvinyl pyrilidone. Maize seeds treated and planted dry, produced greater maize yield than those planted wet. Seeds treated and planted dry yielded more compared to untreated. Treating seeds with 11 and 14 g. a.i./ha imazapyr and planting them dry, gave 5T/ha, which was 25% higher than the untreated. Applying imazapyr in hills gave higher yield than post emergence application. Since very few Striga plants reach flowering in treated plots, herbicide treatment coupled with other cultural Striga control methods such as hand pulling escapes will go along way in containing and eventually reducing Striga in small scale farms in Africa. Such methods are needed to control Striga in the heavily infested soils of Africa, both as stop-gap until genetic resistance in crops becomes available, and to lower the seed bank levels as most genetic resistance fails at high infestation levels.
536 _aConservation Agriculture Program
546 _aEnglish
591 _a0103|AL Maize Program|R98-99CIMPU|AGRIS 0102|AJ|3
593 _aJose Juan Caballero
594 _aINT2340
595 _aCSC
650 1 0 _aChemical control
_91039
650 1 0 _aHerbicides
_gAGROVOC
_91808
650 1 0 _aImazapyr
650 1 7 _aMaize
_gAGROVOC
_2
_91173
650 1 0 _aSeed treatment
650 1 0 _91279
_aStriga
_gAGROVOC
650 1 0 _aStriga hermonthica
650 1 7 _aWeed control
_gAGROVOC
_2
_91308
650 1 0 _aWeeds
_91309
650 1 0 _91314
_aZea mays
_gAGROVOC
700 1 _aCIMMYT|EARO
700 1 _aGressel, J.,
_ecoaut.
_9513
700 1 _aRansom, J.K.,
_ecoaut.
_9271
942 _cPRO
999 _c9827
_d9827