Chewing insects, pollinators, and predators on Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) plants fertilized with dehydrated sewage sludge

Fertilization with dehydrated sewage sludge can speed up the recovery process of degraded areas due to nutrients concentration, favoring the development of pioneer plants such as Acacia auriculiformis A. Cunn. ex Beth (Fabales: Fabaceae) and the emergence of insects. This study aimed the evaluation of chewing, pollinating insects, predators, their ecological indices and relationships on A. auriculiformis plants fertilized with dehydrated sewage sludge. The experimental design was completely randomized with two treatments (with and without dehydrated sewage sludge) and 24 repetitions. The prevalence of chewing insects Parasyphraea sp. (Coleoptera: Chrysomelidae), Nasutitermes sp. (Blattodea: Termitidae), and Tropidacris collaris (Stoll, 1813) (Orthoptera: Romaleidae), defoliation, and ecological indices of abundance of Coleoptera and Orthoptera were observed on fertilized A. auriculiformis. Acacia auriculiformis plants, with a superior number of branches/tree, revealed greater abundance of Coleoptera and Orthoptera, species richness of pollinating insects, defoliation, numbers of Parasyphraea sp. and T. collaris. The ones with larger leaves/branches displayed greater abundance of species richness of Coleoptera and Diabrotica speciosa (Germar, 1824) (Coleoptera: Chrysomelidae). Therefore, the use of A. auriculiformis plants, fertilized with dehydrated sewage sludge, is promising in the recovery of degraded areas due to the ecological indices increase of chewing and pollinators insects and spiders in the analyzed area.

Percentage of importance indice-production unknown: loss and solution sources identification on system

Indices are used to help on decision-making. This study aims to develop and test an index, which can determine the loss (e.g., herbivorous insects) and solution (e.g., natural enemies) sources. They will be classified according to their importance regarding the ability to damage or to reduce the source of damage to the system when the final production is unknown. Acacia auriculiformis (Fabales: Fabaceae), a non-native pioneer species in Brazil with fast growth and rusticity, is used in restoration programs, and it is adequate to evaluate a new index. The formula was: Percentage of the Importance Indice-Production Unknown (% I.I.-PU) = [(ks1 x c1 x ds1)/Σ (ks1 x c1 x ds1) + (ks2 x c2 x ds2) + (ksn x cn x dsn)] x 100. The loss sources Aethalion reticulatum L., 1767 (Hemiptera: Aethalionidae), Aleyrodidae (Hemiptera), Stereoma anchoralis Lacordaire, 1848 (Coleoptera: Chrysomelidae), and Tettigoniidae, and solution sources Uspachus sp. (Araneae: Salticidae), Salticidae (Araneae), and Pseudomyrmex termitarius (Smith, 1877) (Hymenoptera: Formicidae) showed the highest % I.I.-PU on leaves of A. auriculiformis saplings. The number of Diabrotica speciosa Germar, 1824 (Coleoptera: Chrysomelidae) was reduced per number of Salticidae; that of A. reticulatum that of Uspachus sp.; and that of Cephalocoema sp. (Orthoptera: Proscopiidae) that of P. termitarius on A. auriculiformis saplings. However, the number of Aleyrodidae was increased per number of Cephalotes sp. (Hymenoptera: Formicidae) and that of A. reticulatum that of Brachymyrmex sp. (Hymenoptera: Formicidae) on A. auriculiformis saplings. The A. reticulatum damage was reduced per number of Uspachus sp., but the Aleyrodidae damage was increased per number of Cephalotes sp., totaling 23.81% of increase by insect damages on A. auriculiformis saplings. Here I show and test the % I.I.-PU. It is an new index that can detect the loss or solution sources on a system when production is unknown. It can be applied in some knowledge areas.

A method to estimate the damage of Diabrotica speciosa larvae on potato tubers

ABSTRACT The marketable value of potato tubers is affected by damage caused by Diabrotica speciosa, whose larvae create holes on the tubers’ skin and internal feeding tunnels. The estimation of potato tuber damage is usually performed by assessing the external damage to the detriment of feeding tunnels caused by larvae. Thus, we propose a method to estimate the damage caused by D. speciosa larvae, considering the external and internal aspects of the tubers separately. For that, potato plants cv. Agata were grown under different infestations of larvae, measuring the area occupied by the holes and the volume of internal feeding tunnels, relating these data to the total area and volume of the tuber. The methodology used allowed us to characterize an increase in damage in tubers with the highest infestation of larvae. The correlation between internal and external damage caused by D. speciosa larvae was not significant, indicating that external damage alone is not an adequate parameter for the diagnosis of overall tuber quality. However, the method proposed here provides information regarding the volume of pulp consumed by the larvae, the extent of the galleries formed, and the relative volume of damage concerning the total tuber. Moreover, the method proposed here contemplates a more precise analysis of the external area damaged by herbivory relative to the total area of the tuber, which is not commonly considered in studies of underground plant structures.

Desempenho de cultivares de milho na infestação e danos de insetos pragas e nas características fitotécnicas da cultura / Performance of corn cultivars on the infestation and damage of pests insects and phytotechnical characteristics of the culture

A cultura do milho é atacada por um complexo de pragas que reduzem a sua produtividade durante o seu desenvolvimento. Informações sobre as características genéticas de cada cultivar da planta é fator preponderante para determinar os níveis de danos provocados pelos insetos fitófagos. Nesse sentido, o presente estudo teve como objetivo avaliar o desempenho de cultivares de milho convencional (Advanta), crioulo e transgênica (Monsanto VT PRO 3), na percentagem de danos de insetos pragas e sob as características fitotécnicas da cultura. Foram realizadas seis avaliações durante a fase vegetativa do milho, quantificando por planta, a percentagem de danos das seguintes pragas: Diabrotica speciosa, Spodoptera fugiperda, Leptoglossus zonatus e Dalbulus maidis. Ainda foram medidas semanalmente a altura das plantas, o número de folhas e o diâmetro do colmo para cada cultivar de milho. O experimento foi conduzido no campo experimental do Centro Universitário de Goiás Unigoiás, Goiânia-GO, utilizando o delineamento em blocos casualizados com três tratamentos repetidos seis vezes. . Em todas as datas de avaliação, a cultivar convencional e a crioula reduziram em até 66,25 a infestação de D. speciosa, quando comparada as demais cultivares de milho. Essas mesmas cultivares reduziram em até 83,13 % os danos causados por percevejos (Leptoglassus zonatos) (folhas com orifícios) e em até 83,75% os danos causados pela cigarrinha (Dalbulus maidis) (plantas com sintomas de enfezamento vermelho). A cultivar transgênica não apresentou danos causados pela S. fugiperda (folhas raspadas e com orifício) e foi significativamente diferente das demais cultivares. Todas as cultivares de milho analisadas apresentaram valores semelhantes quanto às médias de altura de plantas e número folhas. A cultivar transgênica apresentou maiores valores de diâmetro de colmos. Cultivares de milho apresentam desempenho variável com relação à sua resistência contra insetos e quanto às características fitotécnicas da cultura.

ESTUDIO DE LA ENTOMOFAUNA DE GENOTIPOS DE FRIJOL POR MEDIO DE ANÁLISIS MULTIVARIADO

En el cultivo del frijol existen diversas especies de insectos que pueden ocasionar perjuicios a la productividad y enemigos naturales que pueden ayudar a regular sus poblaciones. El objetivo del presente estudio fue evaluar la entomofauna asociada a 20 genotipos de frijol y correlacionar la interacción entre los insectos utilizando análisis multivariado. Las especies más abundantes en el sistema estudiado fueron Sternechus subsignatus (Curculionidae: Sternechini), Euschistus heros (Hemiptera: Pentatomidae) y Diabrotica speciosa (Coleoptera: Chrysomelidae). Las tres especies presentaron correlación directa entre sí. El cultivo del frijol en estudio presentó tres especies de chinches consideradas importantes plagas. Las especies Cerotoma arcuata (Coleoptera: Chrysomelidae) y Edessa meditabunda meditabunda (Hemiptera: Pentatomidae) presentaron correlación inversa entre sí.

Tolerance in Maize Landraces to Diabrotica speciosa (Coleoptera: Chrysomelidae) Larvae and Its Relationship to Plant Pigments, Compatible Osmolytes, and Vigor

The rootworm Diabrotica speciosa (Germar) is native to South America and causes severe economic losses to several crops due to root feeding and disease spread. In maize (Zea mays L.), losses in production come from larval rootworm attack on plant roots resulting in plant health problems, including stalk lodging. More options for controlling this pest are needed to create well balanced, integrated pest management programs for farmers in this region. Natural sources of tolerance in maize genotypes are important for maize breeding programs, and this study investigated the expression of tolerance in several Brazilian maize landraces to D. speciosa. Plant vigor and compounds associated with plant health, including chlorophylls, carotenoids, glycine betaine, and proline were assessed for each landrace. Five landraces and one maize cultivar were selected based on their levels of antibiosis-resistance to D. speciosa that were determined in a prior screening. The percent reduction in plant growth was used as the measure of tolerance. The landrace Azteca was classified as tolerant to D. speciosa larval feeding, displaying less reduction in plant matter despite having lower plant vigor. This landrace also had higher amounts of chlorophyl and carotenoid pigments, suggesting a positive correlation between tolerance to D. speciosa and higher contents of these photosynthetic pigments. The compatible osmolytes glycine betaine and proline do not seem to be associated with tolerance in maize landraces to D. speciosa larvae. Landrace Azteca seems promising for plant breeding, and repeated field studies are needed to confirm its suitability in maize integrated pest management.