Postharvest insect resistance in maize

Abstract

One of the main challenges for the 21st century is ensuring global food security. Today, maize is the largest staple crop produced worldwide. Postharvest primary insect pests, especially the maize weevil (Sitophilus zeamais) and the large grain borer (Prostephanus truncatus) cause food-grain losses during storage up to 40% of total production, mainly in developing countries. Alternatives for pest management have been explored, including the implementation of hermetic storage structures and the application of chemical insecticides. Nevertheless, in low-income regions, both strategies are rarely accessible to smallholders. Modern breeding programs have endeavored to develop insect-resistant varieties, which diminish postharvest pest losses. In this review, we report the current status and advances in maize kernel-pest interactions, the bases and mechanisms of kernel resistance and their biotechnological perspectives. We demonstrate that the comprehension of resistance mechanisms has been fundamental for the development of new productive and resistant varieties, representing a sustainable alternative for developing countries. Finally, we analyse the biotechnological perspectives of natural kernel resistance in global food security.

Insecticidal Activity of 28 Essential Oils and a Commercial Product Containing Cinnamomum cassia Bark Essential Oil against Sitophilus zeamais Motschulsky

“…Stored-product weevils including the maize weevil, Sitophilus zeamais Motschulsky, and the rice weevil, S. oryzae Linnaeus, belonging to the family Curculionidae, show cosmopolitan distribution, occurring in numerous warm and humid regions worldwide [1]. Maize weevils not only cause significant damage in stored grains including the reduction in nutritional quality, weight and germination rates of seeds in developing countries [2,3], but are also associated with human health due to allergen production and food safety in developed counties as well, since they can transmit fungi including Aspergillus flavus and several types of bacteria [4].…”

Varietal susceptibility of maize to larger grain borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae), based on grain physicochemical parameters

“…As a result, the combination of this both resistance mechanisms (antibiosis and antixenosis) in these three maize varieties, involve complex interactions manifested as grains modifications which lead to limited grain accessibility (physical barriers) and creates toxicity for insects [12].…”

“…The infestation starts in the field and adults attack mainly whole or broken grains and flour during storage [10,11]. In developing countries, this insect is a serious pest of economic importance, causing maize-grain losses during storage ranging from 30% [12] to greater 40% of total production in 6 months [13]. This beetle reduces maize germination, increases the grain's moisture content [14,15] and facilitates the storage contamination by fungi and bacteria [16].…”

Interspecific Competition and Grain-Hosts Selection of Maize Weevil, <i>Sitophilus zeamais</i> (Motsch.) (Coleoptera; Dryophtoridae) and Larger Grain Borer, <i>Prostephanus truncatus</i> (Horn) (Coleoptera; Bostrichidae)

“…(Coleoptera, Dryophtoridae) [3] [4] and the larger grain borer (LGB), Prostephanus truncatus (Horn) (Coleoptera, Bostrichidae) [2] [5]. These two beetles often cause losses in excess of 20% of harvests after six to eight months of storage [6] [7] [8] and constitute a threat of food resource's availability. Maize weevil is a serious pest of economic importance in stored products [6] [9] [10].…”

“…The LGB infestation starts in the field and adults attack mainly the husk, whole or broken grains and flour during storage [2] [13]. The maize-grain loss due to both larval and adult feeding can go up to 30% of total production [6] [8], mainly in developing countries. Prostephanus truncatus is intercepted in Senegal in 2007 [14], and represents since then a threat to maize conservation in the country.…”