Using Essential Oils to Decrease Potato Tubers Sprouting, Rotting and Insect Infestations during Storage at Ambient Temperature

Abstract

Two storage experiments were carried out at El-Mansoura Horticultural Research Station, Dakahalia Governorate, Egypt, during four months of storage in summer seasons of 2013 and 2014 for studying the effect of seven treatments, i.e,. natural essential oils and selecron on storability and quality of potato tubers and reduction percentages in the infestations potato tubers moth (PTM) under Nawwala condition. These treatments such as ; clove oil, garlic oil, lemonion oil, eucalyptus oil, peppermint oil, basil oil, mixture of these oils and selecron. The obtained results revealed that all storage treatments expect, selecron and control gave different significantly in all studied characters. Using peppermint and clove oils recorded the lowest significant values of sprouting percentage, sprout weight, sprout length and weight of loss percentage in both seasons. The highest values of dry matter %, starch% and vitamin C were recorded with peppermint oil, but the lowest sugar percentage was obtained by using the same treatment during two seasons. Results indicated that the effects of essential oils and selecron under storage in Nawwala conditions on Phthorimaea operculla (Zell.) (PTM), after four months of storage, the tubers infestation in control were (48- 48.67%), while the mean reduction percentages of infestation ranged between (94.10- 98.86% and 93.23- 96.84) during two seasons of 2013/2014 respectively. Peppermint oil, eucalyptus oil, clove oil and mixture oils gave highest mean reduction percentages of infestation such as selecron. Generally, the obtained data indicated that all used oils offered the highest protection. Also, the results in laboratory showed that the effects of oil treatments on larvae PTM recorded significantly variation according to the type of oil and time of exposure which showed fatal action on the larvae of PTM. The efficacy of Peppermint oil, Eucalyptus oil, clover oil and Mixer oils were the best. The percent of mortality ranged between (76.14 and 100%) compared with selecron. Also, all oils were used effected inhibitor action on adults. The inhibition of egg laying and reduction percentages ranged between were (47.54 %and 95.02 %) of peppermint oil and galaric oils, respectively. This study recommends that it can be sprayed peppermint oil concentration at (2 cm 3 / L / ton) three times during the storage of potato tubers in Nawwala for (4 months) in order to reduce the proportion of sprouting and weight loss and rotting and get a higher percentage of dry matter, starch and less injuries Pferashh (PTM) in tubers. Finally, it could be recommended with peppermint oil, eucalyptus oil, clove oil and mixer oils were the best during storage to obtain the best characters storage and quality. These natural treatments are very safe and potent in improving storability and greatly decreasing PTM insect infection during storage conditions in Nawwala on potato tubers.