EFFECT OF SOME NATURAL ESSEENITAL OILS ON COWPEA PRODUCTIVITY AND STORABILITY

Abstract

Field and storage experiments were conducted on cowpea cv. El- Balady during 2004/2005 and 2005/2006 seasons, to study the influence of some hybr-distillated essential oils and or their aromatic major components as natural antioxidants and safe botanical insecticides on the agronomical performance of it's plants under high temperature condition of late summer season and on the subsequent storability and insect damage of it 's 5 month stored dry seeds on ambient temperature . In this work , seven natural essential oils of thyme, eucalyptus ,clove , pepper mint, marjoram, lemonine and onion were applied in the field as emulsion foliar sprays. Also, three aromatic major components, i.e. thymol, camphor and menthon (crystal volatiles) and three essential oils, of garlic, majoram and MS were applied during storage as natural fumigants in comparison with Al – phosphide synthetic one. The obtained results of field exp. and it's storage one revealed that, all the applied essential oils greatly improved the agronomical performance of their plants and storability of their 5 months stored seeds in the two seasons. The most significantly effective ones were thyme, lemonine and pepper mint, respectively, those increased dry wt. of their plants by 32.5,31.4 and 27.1%, total fresh pod yield by 50.7, 46.6 and 28.00% , total seed yield by 198.3, 145.5 and110.0% over those of the control. Also, greatly improved storability and viability of their seeds reduced damage from 100% (control) to 2.2, 3.5 and 4.8%, inf. perforated seeds from 100% (control) to 2.7, 6.6 and 8.2% and wt. losses from 60% (control) to 2.0, 4.2 and 5.8% respectively .Regarding the effect of the fumigants during storage, Al-hposphide was the most effective treatment followed by MS. and thymol (natural ones) those respectively reduced seed damage from 100% to 0%, 0% and 7.5%, inf . perforated seeds from 100% to 1.0% , 2.0% and 8.0% , wt. losses from 60% to 0.4%, 1.5 % and 3.0% respectively. For the best yield and storability of cowpea , foliar sprays of theyme or lemonine oils (2m1/L) 4 times during the growing seasons , also for the best storability of 5 month stored seeds , methyl salicylate (MS) oil 0.5 ml/kg seed applied twice as a storage fumigant were the most recommended natural and safe applications.