Are Dried and Powdered Moringa oleifera Lam. Leaves Susceptible to Moths That Feed on Stored Products?

Abstract

The leaves of Moringa oleifera are increasingly used as a food supplement in several countries due to their nutritional composition, which is rich in protein, vitamins, and mineral salts. Foodstuffs can be damaged by several pests when stored in environments with temperatures that are favorable to insect development; therefore, the susceptibility of M. oleifera leaves to attacks of moths that feed on stored products was tested. Tests were carried out on Pyralid Cadra cautella, Corcyra cephalonica, and Plodia interpunctella, as well as Geometrid Idaea inquinata, which were reared on dried whole or powdered M. oleifera leaves, an artificial diet, or an artificial diet supplemented with dried or powdered leaves. The numbers of adults and the development periods with the different diets were recorded. M. oleifera leaves were unsuitable as a rearing medium for all of the species except I. inquinata, although only a few individuals of this species reached the adult stage. The use of an artificial diet of which one-quarter consisted of dried and powdered leaves did not affect the number of progeny or on the biological cycle, showing that the effect was due to the nutritional composition, as well as to the toxic effect. The storage of M. oleifera as powdered leaves is recommended in order to preserve the nutritional characteristics and avoid damage caused by moth larvae.

Enhancing the Nutritional Profile of Tenebrio molitor Using the Leaves of Moringa oleifera

“…When nymphs of the house cricket, Acheta domesticus (L.), and the field cricket, Gryllus bimaculatus De Geer (Orthoptera: Gryllidae), were reared on diets supplemented with 10% of MO leaves, mortality rates were significantly higher compared to the control diet for both insect species tested [ 32 ]. A recent study that evaluated the susceptibility of MO leaves to Pyralid moths showed that both the powdered and the dried MO leaves were not susceptible to moth attacks, as they could not support larval growth for most of the moth species tested and this finding was mainly attributed to the presence of secondary metabolites in the MO leaves [ 12 , 13 , 14 , 33 ].…”

“…Data on the effect of the addition of MO leaves into the diets of edible insects are limited. In one of the few studies available, the final weight of both A. domesticus and G. bimaculatus reared on feed supplemented with 10% MO leaves was significantly lower compared with the weight of larvae fed on the control feed, indicating a lower palatability for the MO feeds [ 33 ]. Overall, although the addition of the MO leaves powder into the diet of TM larvae marginally reduced larval survival, especially at high inclusion rates, it resulted in higher final larva weights, suggesting an improvement of the nutrient profile of the MO feeds compared to bran, which subsequently resulted in the increased larval growth and development.…”

“…to the control diet for both insect species tested [32]. A recent study that evaluated the susceptibility of MO leaves to Pyralid moths showed that both the powdered and the dried MO leaves were not susceptible to moth attacks, as they could not support larval growth for most of the moth species tested and this finding was mainly attributed to the presence of secondary metabolites in the MO leaves [12][13][14]33]. In all cases, values represent means ± SD (n = 8; df = 3; p = 0.05).…”