Field Crop 2024, Vol.7, No.3, 134-144 http://cropscipublisher.com/index.php/fc 137 these effects, although their efficacy can vary based on environmental conditions and the specific pathogens present (Knight et al., 2015). 4.3 Delayed germination and emergence Delayed germination and emergence are other critical issues caused by seedling diseases. The presence of pathogens in the soil can delay the germination process, leading to uneven plant stands and reduced crop uniformity. For example, the use of conservation tillage practices has been associated with reduced plant populations and delayed emergence due to increased seedling disease pressure (Colyer and Vernon, 2005; Knight et al., 2015). Additionally, the timing of sowing and planting density can influence the extent of these delays. Late sowing dates, combined with high planting densities, have been shown to exacerbate the effects of seedling diseases, leading to further delays in germination and emergence (Yuan et al., 2017). Seedling diseases have a profound impact on cotton crop establishment by increasing seedling mortality rates, reducing plant vigor and growth, and causing delayed germination and emergence. Effective management practices, including the use of fungicides, insecticides, and appropriate tillage methods, are essential to mitigate these adverse effects and ensure successful crop establishment. 5 Impact on Cotton Yield 5.1 Yield reduction statistics Seedling diseases significantly impact cotton yield by reducing plant populations and causing plant stress. For instance, research has shown that seedling diseases can lead to a reduction in plant populations, which directly correlates with lower yields. In a study comparing different tillage systems, it was found that plant populations were significantly different between tillage treatments, affecting the overall yield (Colyer and Vernon, 2005). Additionally, the presence of Verticilliumwilt has been shown to decrease lint and seed yield in susceptible cotton genotypes (Bauer and Roof, 2004). Thrips infestations can also lead to substantial yield losses, with reports indicating potential lint yield reductions of up to 30-50% due to severe infestations (Karar et al., 2020). 5.2 Quality of cotton fibers The quality of cotton fibers is also adversely affected by seedling diseases. Verticillium wilt, for example, significantly impacts fiber properties such as micronaire, maturity ratio, short fiber content, nep count, fineness, and immature fiber content. Infected plants showed a decrease in micronaire and maturity ratio, indicating poorer fiber quality (Bauer and Roof, 2004). Similarly, the presence of various pests and diseases in transgenic cotton cultivars in Pakistan has been shown to affect fiber quality traits, with some cultivars exhibiting higher susceptibility to pests and diseases, leading to compromised fiber quality (Karar et al., 2020). 5.3 Economic implications The economic implications of seedling diseases on cotton crops are profound. Yield reductions and compromised fiber quality translate to lower market value and reduced profitability for cotton growers. For instance, the economic impact of fall armyworm infestations on cotton yields has been documented, with significant yield losses reported across various studies (Overton et al., 2021). The economic thresholds for managing these pests are crucial for minimizing losses. Additionally, the cost of managing seedling diseases through fungicide applications and other control measures adds to the overall production costs. In Pakistan, the economic returns from different transgenic cotton cultivars varied significantly, with some cultivars showing higher gross and net incomes due to lower pest susceptibility and higher yields (Karar et al., 2020). This highlights the importance of selecting disease-resistant cultivars to maximize economic returns. 6 Disease Management Strategies 6.1 Cultural practices Effective management of seedling diseases in cotton crops is crucial for ensuring healthy crop establishment and optimizing yield. Various strategies can be employed to manage these diseases, including cultural practices, chemical control, and biological control, often integrated into an Integrated Pest Management (IPM) approach.
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