Critical period for weed control in direct seeded red pepper (Capsicum annum L.)

Abstract

Direct seeded red pepper is a cash crop in Kahramanmaraş province of Turkey as well as some other nearby provinces. Weeds are a major constraint in red pepper production. Field studies were conducted to determine critical period for weed control (CPWC) in direct seeded spice pepper in Kahramanmaraş, in 2008 and2009.The CPWC in red pepper based on a 2.5%, 5% and 10% acceptable yield loss (AYL) was calculated by fitting logistic and Gompertz equations to relative yield data. The CPWC in red pepper was determined from 0 to 1087 growing degree days (GDD) in 2008 and from 109 to 796 GDD in 2009 for 10% AYL after crop emergence in red pepper. For 2.5-5% AYL, the CPWC starts with germination and lasts until harvest. Direct seeded red pepper is very vulnerable to weed competition and weed control programs for direct seeded spice pepper in Turkey should include pre-emergence and residual herbicides.Keywords: acceptable yield loss (AYL), critical period of weed control (CPWC), direct seeded pepper, red pepper (Capsicum annum L.), spice pepper, weeds.

Assessment of Weed Competition Critical Period in Sugar Beet

“…weeds (E. crus-galli, A. retroflexus, C. album, X. strumarium,) were the same type seen and analyzed in earlier studies carried out to find out the CPWC in other types of crops in Turkey (Isik et al 2006;Tursun et al 2012). Such weed species are abundant and important weeds in Turkey.…”

“…The estimation of GDD related to 90%, 95% and 97.5% relative yield was calculated from Equation 2 for each year and then the same was applied for the DAE. In the present study, the greatest yield decrease of 5% was randomly assigned as the value above which yield decrease was determined as being undesirable (Tursun et al 2012).…”

“…The extent of the CPWC in sugar beet was 45, 34 and 24 days in 2012 and 60, 46, 32 days in 2013 with 2.5, 5 and 10% acceptable yield loss levels (AYL), respectively. A 5% yield loss is accepted as a rule for most crops in Turkey (Isik et al 2006;Tursun et al 2012). Based on 5% acceptable yield loss (AYL), the beginning of CPWC in sugar beet was identified 2012 -1.9 (0.6) -6.8 (25.7) 557.9 (78) 713.5 157.72013 -2.7 (0.9) -1.2 (40.3) 622.9 (68) 446.0 (74.1)…”

“…The end of CPWC rose as the AYL decreasing from 10% to 2.5% ( Figure 2). The differences between the end of CPWC in both years were possibly because of the differences in weed populations between the growing seasons (Table 1) and this might have been due to variations in sowing time and rainfall amounts in each respective years (Tursun et al 2012).…”

Critical period of weed interference on total polyphenol content in quinoa

“…In a similar study with peas, Singh et al (2016) reported increased weed density until 60 DAE and then observed a downward trend and concluded that most weeds emerge up to 60 DAE. Weed density was also affected by environmental conditions in both seasons (Table 2); weeds faced high precipitation in the early stages, which could cause their higher germination and emergence and result in higher weed density (Tursun et al, 2012). There was also an increase in temperature during the two seasons (Table 2), and this increase can accelerate weed seed germination and increase competition between different species (Giménez et al, 2013).…”