Diatomaceous earth (DE) has the potential to decrease pest damage to plants both indirectly by being a source of silica if applied as a soil amendment and directly as a physical barrier if applied to foliage. For applicability in Louisiana sugarcane, DE would need to be effective at controlling the sugarcane borer (SCB), the primary economic pest, while not harming natural enemies like the red imported fire ant (RIFA) that provide biological control. We examined DE formulated for agricultural use by evaluating its potential as a sugarcane soil amendment and a foliar treatment. We determined impacts of a DE soil amendment on SCB damage and yield in a field test then evaluated if the amendment negatively impacted RIFA survival in a laboratory assay. Using potted plants, we assessed efficacy of DE foliar applications against SCB followed by a visual assessment of product longevity in the field. We found that the DE soil amendment did not alter SCB damage or yield but neither did it impact RIFA survival. Unlike the soil amendment, foliar application in a rain-free environment decreased SCB damage to stalks. However, the product did not last long on leaves or stalks under typical Louisiana field conditions. Given that the most used insecticide in sugarcane only requires 1-2 applications per year and does not disrupt biological control while DE would require many costly applications due to plant growth rates and precipitation levels, we suspect that DE is not currently a good fit for use with Louisiana sugarcane production.

The sugarcane industry has been suffering from unstable productivity on commercial fields. The major factors causing this problem are mechanized harvesting damage to cane clumps in the field and the slow process of releasing and adopting new sugarcane cultivars. By utilizing new micropropagation processes involving the extraction of apical meristem from new cultivars and biofactory methods for multiplying the material, it is possible to produce an extraordinary number of sugarcane seedlings to provide nurseries rapidly with new cultivars for planting on commercial fields. The goal of this study was to evaluate several irrigation strategies (IS) to determine the best one for supplying the biofactory sugarcane seedlings water requirements, under conditions of different volumes of substrate (VS): 56, 73, 93 and 125 cm3. The irrigation management experiment comprised eight IS based on different periods of accumulated reference evapotranspiration (ETo). We found that the irrigation application must occur at intervals below 30 mm of accumulated ETo. IS1 (maintenance of soil moisture at field capacity) results in a larger number of tillers, longer extension of the primary stalks, and enhanced dry matter (DM) yield independent of VS. The VS factor accounted for statistical differences in sugarcane survival rate and morphological characteristics, but only for low initial soil moisture conditions. The intermediate VS of 73 cm3 was the best option for plants to thrive in the field; larger VS (93 and 125 cm3) produced young plants with many leaves, which transpire a lot in the field, increasing the chances of early death under water stress after planting; the smaller VS (56 cm3) resulted in young plants with small root systems and minimal water reservoirs, resulting in lower survival under drought conditions.