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

Abstract

Maize (Zea mays L) is one of main nutrients sources for humans and animals worldwide. In Africa, storage of maize ensures food resources availability throughout the year. However, it often suffers losses exceeding 20% due to insects such as the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae), major pest of stored maize in the tropical countries. This study aims to select resistant varieties to reduce maize storage losses and explain the physicochemical parameters role in grains susceptibility. In the first study, maize grains were artificially infested under no-choice method with insects. Susceptibility parameters such as weight loss, grain damage, number of emerged insects, median development time and susceptibility index varied significantly through maize varieties. Dobie susceptibility index (SI) was assessed as a major indicator of resistance. The most resistant varieties were Early-Thaï, DMR-ES and Tzee-Yellow. Conversely, Synth-9243, Obatampa and Synth-C varieties were susceptible. SWAN, Across-Pool and Tzee-White were classified as moderately resistant varieties. The insect reproductive potential was significantly different in the nine maize varieties and Early-Thaï, DMR-ES and Tzee-Yellow varieties were the least favourable host. To assess the relationship between grains physicochemical characteristics and varietal susceptibility, moisture, total phenolics, palmitic acid, proteins, amylose, density and grain hardness were evaluated according to standardized methods. Palmitic acid, SI, insects emerged and grain damage were significantly and positively correlated with each other, and negatively correlated with grains hardness, phenolics and amylose contents. Maize susceptibility index was significantly and negatively correlated to amylose, and phenolics contents and positively correlated to palmitic acid content. This

Biological Control Against Four-Stored Product Beetles Pests by Using Cytoplasmic Polyhedrosis Virus (Cypovirus1)

“…Drugstore beetle was the most common stored product beetles with an infection rate of 67.20% (Table 1) and the incidence was particularly high in stored products (Ground anise, Ground cumin, all type of pasta, Nigella sativa, and Wheat flour these results were illustrated with (Figure 1), [4,5] grown in Khulais (85.19%) and Taif, Rabigh, Jeddah, Bahra, Makkah, and Aljummum (74.10%, 71.30%, 71.29%, 67%, 54.63%, and 46.30%, respectively. Rice weevils ranked second (54.37%) and were mostly similarly distributed in all the regions (Khulais, Rabigh, Taif, Makkah, Jeddah, Bahra and Aljummum, 91.67%, 67.6%, 56.48%, 52.78%, 48.15&, 39.82% and 38.89%, respectively [1,2]. In addition, the Darkling beetle recorded a high infection rate (50.93%) in the Khulais region, while, recorded a low infection rate in Aljummum (29.63%) [1].…”

“…It is one of the most important global insects that attack stored products, especially stored food grains. Were the attack grain cereals, nuts, beans, and biscuits, causing loss and damage [1][2][3]. The drug beetle (Stegobium paniceum) crosses insects that have widespread worldwide and are also multi-existent in different environments [4].…”

Morphophysical and biochemical traits involved in maize grain varietal susceptibility to the maize weevil, Sitophilus zeamais (Coleoptera, Curculionidae)

“…Maize phenolics are involved in the resistance to both surface tissues formation (antixenose action) and anti-feedants and toxic properties of these free form acids (antibiose action) (Classen et al, 1990;García-Lara et al, 2004). In maize, antibiosis mechanisms against S. zeamais and Prostephanus truncatus have been found to be closely associated to the action of biochemical compounds such as phenolic acids (Sen et al, 1994;Arnason et al, 1997;López-Castillo et al, 2018;Ngom et al, 2020). Possible inhibition of insect neuroreceptors by phenolic compounds has been suggested by Fixon-Owoo et al (2003) even if the mechanisms and the determinant of this inhibition are still unknown as well as their association in host insect resistance.…”

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)

“…Maize variety not treated with insecticides used in these experiments was SWAN, provided by Peanut and maize Seed Growers' Cooperative (COPROSA-Nioro du Rip-Senegal). Preliminary tests of maize varieties susceptibility against S. zeamais and P. truncatus indicated that SWAN variety has same resistance status (moderately resistant) for these two insects species [27] [28]. Maize grains were placed for three weeks in a freezer (at −5˚C approximately) to eliminate any potential infestation before use for experimentation.…”