The peduncular mold in avocado and its control

This pathology does not usually affect the fruit internally; it is, rather, a problem affecting the appearance of the fruit, and its aesthetic quality. However, some authors consider that it could be a symptom prior to the appearance of “stem end rot” in the avocado. Moreover, its economic relevance is high. The more fruit affected at the destination, the higher the amount the claim tends to be. It is a problem that is not detected at the source; it develops during transport. Control of the peduncular mold of avocadosGiven that the problem is caused by saprophytic fungi, we have identified Alternaria sp and Cladosporium sp whilst other researchers have also cited Botrytis sp, Colletotrichum sp, and Lasiodiplodia sp, sanitation measures, both in the field and in the packinghouses are important. However, the economic relevance of the problem makes it advisable to implement more effective control measures. Treatments with the fungicide Prochloraz can be applied and be highly effective, but its application prevents export to some countries, including the USA, where its MRL (Maximum Residue Limit) is at the Limit of Detection. Furthermore, the prohibition of Prochloraz in the European Union is expected soon. Confronting the situation, CITROSOL has been investigating the use of Sistema Citrocide® Palta (Citrocide® AVO System) to control peduncular mold for some years. In 2018 we started trials and can now confirm that with the implementation of the Citrocide® AVO System we have successfully achieved control of peduncular mold. The Citrocide® AVO System is a highly effective alternative for peduncular mold control, without any problem of residues in any country importing avocado as the Citrocide® PC, that is applied in the System does not leave a residue. Below, we have summarized the results obtained by comparing its efficacy with active Chlorine disinfection and with the application of Prochloraz, in semi-industrial tests undertaken in Peru and Chile. Our results are presented in Table 1. While Prochloraz controlled the appearance of the peduncular mold with 79% efficiency, the Citrocide® Avocado System increases the efficiency up to 84%.Finally, in Figure 2 the results obtained in a test carried out under industrial conditions in a packinghouse in Peru last September are shown. This packinghouse has a Citrocide® AVO System installed via which Citrocide® PC was applied at 0.7%. The results show the efficacy of the System greater than 80% with less than 20% of the fruit affected after a period of 29 days of cold storage at 5ºC; At 29 days, all the fruit that had not been washed in the System had developed peduncular mold and, in the same manner, traditional in-line washing with soap was also ineffective. It is noteworthy that these results were obtained with quite a dirty lot of fruit on arrival at the packinghouse. Citrocide® AVO System is a guarantee of Food Safety, eliminating all coliform bacteria and molds from the surface of the fruit (results presented in ProHass Informa in March 2021). Now we can see how the Citrocide® AVO System is highly effective in mitigating, even fully controlling peduncular mold. The treatment with Citrocide® PC does not leave any residue on the fruit. It is certified as an input for organic agriculture according to the European Standard REG (EC) 834/2007. Table and figuresTable 1. Summary of results obtained with the Citrocide® AVO System in the control of peduncular mold compared with the use of Prochloraz, and with a disinfection of the avocado using 200 ppm of active Chlorine. The results show the averages of the tests carried out with 4 batches of fruit. Results obtained after 40 days of refrigerated storage at 5-6ºC.Figure 2. Evolution of peduncular mold in cv. Hass subjected to different treatments (Perú, Sept. 2021)