The influence of formulation on Trichoderma biological activity and frosty pod rot management in Theobroma cacao

Abstract

Frosty pod rot (FPR), caused by Moniliophthora roreri, is responsible for significant losses in Theobroma cacao. Due to limited options for FPR management, biological control methods using Trichoderma are being studied. Combinations of three formulations and two Trichoderma isolates were studied between May 2009 and April 2011. The formulations were 0Á3 mL L À1 of the surfactant BreakThru 100SL (BT), a mixture of 1% w/v Sure-Jell (source of pectin) and 1% w/v potato dextrose broth (PDB) (PP), and an invert oil emulsion of 50% v/v corn oil/2Á5% w/v lecithin/0Á5% w/v PDB (COP). Water and fungicide, copper oxychloride, were included as controls. Humidity chamber studies indicated that Trichoderma conidia germinated in all formulations if free water was maintained, while only the COP formulation supported germination under drying conditions. In the field, Trichoderma ovalisporum DIS-70a and Trichoderma harzianum DIS-219f were applied monthly in each of the three formulations at a rate of 180 mL per tree, 2Á46 9 10 7 conidia per mL. The COP/DIS-70a formulation provided the largest yield increase compared to all other treatments, including the fungicide control. Averaged over the 2 years, the COP formulation increased yield to 30Á7% healthy pods compared to 9Á7% healthy pods in the water control. Although the formulation/isolate combinations did not consistently increase endophytic colonization, the PP/DIS-219f, COP/DIS-219f and COP/DIS-70a combinations increased total endophytic/ epiphytic colonization by Trichoderma. The invert corn oil formulation of DIS-70a significantly enhanced yield of healthy cacao pods over 2 years providing a promising model for optimizing Trichoderma-based biocontrol strategies.

Formulation of Trichoderma asperellum TV190 for biological control of Rhizoctonia solani on corn seedlings

“…Several oil-based formulations with T. asperellum have been developed to control cacao black pod disease caused by Phytophthora megakarya, in which the half-life of the conidia reached 22.5 and 5 weeks in aqueous and oil suspension, respectively (Mbarga et al 2014). Oil and aqueous formulations have been proven to control frosty pod rot caused by Moniliophthora roreri on cocoa (Crozier et al 2015), finding that an inverted corn oil formulation significantly enhanced cocoa yield, providing a promising model for optimizing Trichoderma-based biocontrol strategies. Finally, some vegetable oils are able to absorb UV radiation (Montenegro and Santagati 2019) suggesting the possibility to use them as UV blockers.…”

Control in vivo de Moniliophthora roreri en Theobroma cacao, utilizando polisulfuro de calcio y silicosulfocálcico

“…También se han adelantado estudios, principalmente en Costa Rica y México, con organismos antagonistas, como Trichoderma spp. (10,11,12,13), y extractos vegetales (14,15,16), pero no se encontraron reportes que indiquen su aplicación exitosa en cultivos a escala comercial.…”

Formulation Technology of Biocontrol Agents: Present Status and Future Prospects

“…COP/DIS70a formulation resulted in a maximum increase in yield as compared to other treatments (Crozier et al 2015).…”