Identification of weeds resistant to glyphosate in corn growing areas of region 12

This study indentified the determined weeds resistant to Glyphosate of farmers from the Corn growing areas of South Cotabto,Nort Cotabato, Sarangani Province and Sultan Kudarat in Region 12 , Philippines. A descriptive observational, qualitative and experimental design was employed involving Focus Group Discussion with 20-30 Key informants from the province, Field Observation and gathering of weeds sample present in the field. Data were transcribed verbatim and analyzed using Thematical analysis from the response during FGD’s. Experiment using different doses of herbicide was also conducted to the determined Glyphosate resistant weeds by the farmers. Frequency of weed occurrence were also gathered through quadrat. Findings indicated that farmers in particular provinces were adding adjuvants (additional mixtures to the ) such as used cooking oil, fertilizers and other herbicide because of the farmer’s belief of effective mitigation for determined weeds in the province,It was also observed in the Frequency of Weed Occurrence that Itch grass, banig-banig , tanglad-tanglad and Milk weed has the highest frequency. However, in the experiment of different doses including the recommended dose with 16TBSP/16 liters knapsack sprayer, 32TBSP/16liters knapsack sprayer and 8TBSP/16liters knapsack sprayer was observed that lower dose has significantly showed a higher survival rate while the over and recommended dose following the manufacturer’s guidelines shows 0% survival rate. The study concluded that the presence of diverse weed species across Region 12's corn fields underscore the importance of region-specific weed management strategies. Consistent application of the recommended glyphosate dose effectively controls weed populations; however, the use of sub-lethal doses by farmers has led to significant survival of certain weeds, suggesting the emergence of glyphosate resistance. This resistance can compromise long-term weed control and crop productivity. Therefore, adherence to proper herbicide application rates and integrated weed management practices are critical to mitigate resistance development and sustain effective control measures. Further studies should investigate the genetic basis of resistance in prevalent weed species to develop targeted management strategies within Region 12.