RNAi Targets in Agricultural Pest Insects: Advancements, Knowledge Gaps, and IPM

The unprecedented target-specificity of double-stranded RNA (dsRNA), due to its sequence-specific mode of action, puts dsRNA at the forefront of biosafe insecticide technology. Since 2007, sensitive target genes have been identified in numerous crop pest insects, with an end goal of applying RNA interference (RNAi) in pest management. Key RNAi targets identified include genes involved in (1) feeding and digestion, (2) production of dsRNases, (3) resistance to insecticides and plant allelochemicals, (4) reproductive fitness, and (5) transmission of plant viruses. Despite the advances, there remain critical knowledge gaps in each of these areas. Particular emphasis must be placed on ensuring RNAi's compatibility with integrated pest management (IPM), via further identification of molecular targets that reduce crop damage while sustaining pest (host) populations for highly specialized biocontrol agents, the latter representing a core pillar of IPM.

Extraction of Pest Insect Characteristics Present in a Mirasol Pepper (Capsicum annuum L.) Crop by Digital Image Processing

One of the main problems in crops is the presence of pests. Traditionally, sticky yellow traps are used to detect pest insects, and they are then analyzed by a specialist to identify the pest insects present in the crop. To facilitate the identification, classification, and counting of these insects, it is possible to use digital image processing (DIP). This study aims to demonstrate that DIP is useful for extracting invariant characteristics of psyllids (Bactericera cockerelli), thrips (Thrips tabaci), whiteflies (Bemisia tabaci), potato flea beetles (Epitrix cucumeris), pepper weevils (Anthonomus eugenii), and aphids (Myzus persicae). The characteristics (e.g., area, eccentricity, and solidity) help classify insects. DIP includes a first stage that consists of improving the image by changing the levels of color intensity, applying morphological filters, and detecting objects of interest, and a second stage that consists of applying a transformation of invariant scales to extract characteristics of insects, independently of size or orientation. The results were compared with the data obtained from an entomologist, reaching up to 90% precision for the classification of these insects.

A scientific note of pest-insects associated with stingless bee hive Melipona eburnea in the Ecuadorian Amazon Region

Bees are the primary pollinators in nature. However, climate change, excessive use of fertilizers and invasive species have caused the decline of bee colonies. Therefore, this study aimed to analyze the presence of pests in colonies of Melipona eburnea. For this, the colonies of M. eburnea were examined during the honey extraction process. We found 4 different pests associated with the physical conditions of colonies and the fragile defense of the bees against the invaders. In conclusion, this report of the presence of pests is to alert researchers and meliponicultures to prevent the decline of stingless bees.

Comparison of the effectiveness of phostoxin fumigants for controlling insect pests warehouse Lassioderma serricorne and Pholcus phalangioides

Insects warehouse pests contained in commodities, especially tobacco, can cause a decrease in the quantity and quality of commodities. The main pest insects found in tobacco storage warehouses are Lassioderma serricorne and Pholcus phalangioides. This study aims to analyze and compare the effectiveness of phostoxin fumigants to control insect pests L. serricorne and P. phalangioides. Methods used in this study include preparation of test insects, fumigation application, identification, calculation of mortality, and data analysis. The data were analyzed using one way ANOVA test. The results showed that there was a significant difference in morphility between groups of test insects. The highest mortality was in the group of test insects L. serricorne, which indicated that phostoxin fumigants effectively controlling barn insect pests, especially L. serricorne. To control insect pests warehouses in the future, it is recommended to use biopesticides to be safer for food.

Comparison of the effectiveness of fumigant storin to control insect pests warehouse Lassioderma serricorne and Pholcus phalangioides

Insects warehouse pests contained in commodities, especially tobacco, can cause a decrease in the quantity and quality of commodity. The main pest insects found in tobacco storage warehouses are Lassioderma serricorne and Pholcus phalangioides. This study aims to analyze and compare the effectiveness of the use of fumigant storin to control insect pests L. serricorne and P. phalangioides. Methods used in this study include preparation of test insects, fumigation application, identification, calculation of mortality, and data analysis. The data were analyzed statistically using the One Way ANOVA test. The results showed that there was a significant difference in morphility between groups of test insects. Mortality is highest in the L. serricorne test insect group, which indicates that fumigant storin is very effective in controlling barn pest insects, especially L. serricorne. To control insect pests warehouses in the future, it is recommended to use biopesticides to be safer for food.

Extinderea gamei de preparate biologice de protecție a plantelor pentru agricultura convențională și ecologică

The global population is projected to increase by 30 % to 9,2 billion by 2050 and this increased population density is estimated to increase demand for food production by 70 %. One of the principal di-rections of biological plant protection is elaboration of technologies for production and application of bio-logical preparations for combat not only of the noxious insects but also of pathogen agents which cannot be efficiently combated by other means of biological control. This report presents the results of state reg-istration of 5 baculoviral, 1 bacterial and 3 fungal preparations for combating pest insects, phytopathogen agents and nematodes.

Coffee crop weeds: refuge and food source for pests’ natural enemies

Weeds in coffee crops have diverse ecosystem services, such as sheltering and feeding natural enemies of pest insects. This study aimed to identify the potential of coffee weeds as food and refuge for natural enemies in shaded and sun coffee crops. Weeds were sampled in a 100 m transect installed in each type of coffee crop. Malaise traps and sweep-nets were both used to capture insects every 15 days for five months. After identifying the dominant weeds, observations and a direct recollection of insects were carried out at three different hours during three days. Faunistic analyses were performed, as well as the Bray and Curtis similarity analysis and the Student's t test. Emilia sonchifolia, Acmella oppositifolia, Bidens pilosa were predominant in the free exposure sun plantation coffee crops and Commelina diffusa, Salvia palifolia, Stachytarpheta cayennensis in under shade coffee crops. High insect activity was found between 11:30 am-12:00 pm. In these weeds, we found about 15 families, the most important were Formicidae, Braconidae, and Coccinellidae. We concluded that the shaded coffee crops exhibited a natural enemy community similar to that of the sun. Through this exploratory study, we verified that weeds harbor a diversity of natural enemies important to the coffee agroecosystems.

Inhibition of serotonergic signaling induces higher consumption of both sucrose solution and toxic baits in carpenter ants

Biogenic amines play an important role in the regulation of appetitive responses in insects. Among them, serotonin (5-HT) regulates feeding-related processes in numerous insect species. In carpenter ants, 5-HT administration has been shown to depress feeding behavior, thus opening the possibility of using 5-HT modulation in control strategies against those species considered as pest. Here we studied if administration of a 5-HT antagonist, ketanserin, promotes feeding of a sucrose solution and a toxic bait in carpenter ants Camponotus mus. We found that 3 h after a single oral administration of ketanserin, the mass of sucrose solution consumed by carpenter ants increased significantly. A similar effect was found after a chronic administration that lasted 5 days. Yet, ketanserin did neither affect the intake rates nor the activity of the pharyngeal pump that mediates feeding dynamics. In addition, ketanserin promoted the consumption of a toxic bait based on boric acid. Our results thus show that feeding motivation and consumption of both sucrose solution and a toxic bait can be enhanced via prior administration of ketanserin. We discuss the possible mechanisms underlying these effects and conclude that understanding basic physiological and neural principles that underlie feeding motivation allows establishing more efficient control strategies for pest insects.