Rodrigo S. Ramos

Functional Response of Three Species of Predatory Pirate Bugs Attacking Eggs of Tuta absoluta (Lepidoptera: Gelechiidae)

ABSTRACT The functional response and predation parameters of three species of predatory pirate bugs Amphiareus constrictus (Stal), Blaptostethus pallescens Poppius, and Orius tristicolor (White) (Hemiptera: Anthocoridae) were evaluated at four different densities of eggs of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). Experiments were conducted in Petri dishes containing a tomato leaf disk infested with the pest eggs, and maintained inside growth chamber with environmental conditions of 25±2°C, 70±10% relative humidity, and a photoperiod of 12:12 (L:D) h. A. constrictus and B. pallescens showed a type III functional response where predation increased at a decreasing rate after egg density was higher than 12 per leaf disk, reaching an upper plateau of 18.86 and 25.42 eggs per 24 hours, respectively. By contrast, O. tristicolor showed a type II functional response where the number of eggs preyed upon increased at a decreasing rate as egg density increased, reaching an upper limit of 15.20 eggs per 24 hours. The predator equations used in this study estimated handling time of 1.25, 0.87, 0.96 h for A. constrictus, B. pallescens, and O. tristicolor, respectively. The lower handling time and possible higher attack rate of B. pallescens suggests a higher efficiency and probably greater impact on the pest population. If conservation or classical biological control of T. absoluta is to be implemented, then prioritizing which natural enemy species is the most efficient is an important first step.

A low-cost trap for Cerambycidae monitoring in forest plantations in Brazil

The objective of this work was to evaluate the use of a low-cost trap to capture Cerambycidae in different seasons in planted forests in Brazil. Thirty polyethylene-terephthalate trap bottles per hectare were used, disposed at every 50 m. The traps were red painted and contained glass flasks with a mixture of ethanol, methanol and benzaldehyde. There were soap and water at the trap bottom. The traps were checked biweekly for beetle presence. Sampling time required one minute per sample, and traps were easy to use. Total sampling cost, including materials and labor, was US

Ocorrência e distribuição espacial e temporal do coleóptero Naupactus curtus em cafeeiros de Minas Gerais, Brasil

13.46 per sample. Six Cerambycidae species were captured along the dry and rainy seasons.

Toxicity of new pyrethroid in pest insects Asciamonuste and Diaphania hyalinata, predator Solenopsis saevissima and stingless bee Tetragonisca angustula

There were no reports of Naupactus curtus in Minas Gerais, and the few occurrences in other Brazilian States bring is little of information about its spatial distribution on coffee plants. This work aimed to report the occurrence of this potential in Minas Gerais and study its their spatial and temporal distribution dynamics on crops of Coffea arabica. The study was conducted in coffee plants in Ponte Nova and Jaboticatubas, with the evaluation of density being monthly. N. curtus was found in two areas in Minas Gerais, presenting higher densities at the edges of the crops.

Toxicity of insecticides to Chrysodeixis includens and their direct and indirect effects on the predator Blaptostethus pallescens

ABSTRACT There is increasing demand for new products for vegetable pest management. Thus, the aim of this study was to assess the toxicity of pyrethroids with acid moiety modifications to measure the insecticidal activity of these compounds on the lepidopteran vegetable pests Diaphania hyalinata (L.) (Lepidoptera: Pyralidae) and Asciamonuste (Latreille) (Lepidoptera: Pieridae) and evaluate their selectivity for the predatory ant Solenopsis saevissima (F. Smith) (Hymenoptera: Formicidae) and pollinator Tetragonisca angustula (Latreille) (Hymenoptera: Apidae: Meliponinae). Racemic mixtures of five new pyrethroids (30 µg molecule mg−1 insect body weight) resulted in high (100%) and rapid (stable LD50 after 12 h) mortality in D. hyalinata and A. monuste. In A. monuste, the trans-pyrethroid [12] isomer showed similar toxicity to permethrin. For D. hyalinata, the trans-pyrethroid [9] isomer and cis-pyrethroid [10] isomer were as toxic as permethrin. Due to their low selectivity, these new pyrethroids should be applied on the basis of ecological selectivity principles to minimize impacts on nontarget organisms S. saevissima and T. angustula.

Mapping global risk levels of Bemisia tabaci in areas of suitability for open field tomato cultivation under current and future climates

The soybean looper Chrysodeixis includens (Lepidoptera: Noctuidae) is a pest of the soya bean, and increasing populations have been observed on several crops in Brazil. Control of this pest is accomplished using insecticides, particularly with new products recently launched in the market. The effectiveness of these insecticides against C. includens and their impact on natural enemies need further study. Therefore, this study aimed to determine the toxicity of nine insecticides for C. includens and their effects on the Blaptostethus pallescens. Toxicity was increased via the addition of an insecticide synergist, and behavioural changes in Blaptostethus pallescens, an anthocorid predator of C. includens, were assessed. Except for acephate, all other insecticides showed high toxicity to C. includens (mortality >80%). The estimated lethal time (LT50) for C. includens was shorter for methomyl, cartap and spinosad than others six insecticides tested in this work. Chlorantraniliprole, chlorfenapyr, deltamethrin, flubendiamide, indoxacarb and spinosad showed selectivity for the predator B. pallescens and exhibited a lower toxicity to the predator than to C. includens. The detoxifying enzymes monooxygenase and glutathione S‐transferase may be involved in the selectivity mechanisms of these insecticides for the predator based on the results obtained with the synergized insecticides. Only the insecticides cartap, indoxacarb and spinosad changed the behaviour of the predator B. pallescens. These three insecticides are repellent, and the predator avoids them. However, the predator tended to remain on the surface treated with flubendiamide longer. Our results suggest that the insecticides chlorfenapyr, chlorantraniliprole, flubendiamide, spinosad and indoxacarb are the most promising compounds for use against C. includens. These compounds also preserve populations of B. pallescens and allow more sustainable integrated pest management programmes.

Host range and genetic strains of leafminer flies (Diptera: Agromyzidae) in eastern Brazil reveal a new divergent clade of Liriomyza sativae

The whitefly, Bemisia tabaci, is a major threat to tomato Solanum lycopersicum and ranks as one of the world’s 100 most invasive pests. This is the first study of B. tabaci (Biotype B and Q) global distribution, focusing on risk levels of this invasive pest, in areas projected to be suitable for open field S. lycopersicum cultivation under climate change. This study aims to identify levels of risk of invasive B. tabaci for areas of suitability for open field S. lycopersicum cultivation for the present, 2050 and 2070 using MaxEnt and the Global Climate Model, HadGEM2_ES under RCP45. Our results show that 5% of areas optimal for open field S. lycopersicum cultivation are currently at high risk of B. tabaci. Among the optimal areas for S. lycopersicum, the projections for 2050 compared to the current time showed an extension of 180% in areas under high risk, and a shortening of 67 and 27% in areas under medium and low risk of B. tabaci, respectively, while projections for 2070 showed an extension of 164, and a shortening of 49 and 64% under high, medium and low risk, respectively. The basis of these projections is that predicted temperature increases could affect the pest, which has great adaptability to different climate conditions, but could also impose limitations on the growth of S. lycopersicum. These results may be used in designing strategies to prevent the introduction and establishment of B. tabaci for open-field tomato crops, and assist the implementation of pest management programs.

Acute Toxicity and Sublethal Effects of Botanical Insecticides to Honey Bees

Leafminer flies are phytophagous and cosmopolitan pests. Leafminer fly outbreaks and damage to cultivated plants have steadily increased in several regions in the world. In the present study, we report host range, geographical distribution, Wolbachia infection and mitochondrial strains of leafminer fly species from eastern Brazil. Four leaf miner fly species were identified using cytochrome c oxidase subunit I DNA barcoding. Liriomyza sativae is the main pest as a result of its high polyphagy and wide distribution. Liriomyza brassicae, Liriomyza huidobrensis and Calycomyza malvae are important in Brassicaceae, Curcubitaceae and Malvaceae crops, respectively. There is no relationship among host range, geographical distribution and mitochondrial strains of leafminer fly species. We did not find Wolbachia infection in any of the specimens collected. Phylogeographical analyses suggests that there are four strains of L. sativae in the world, one of which is endemic from Brazil. The lack of shared haplotypes between Brazilian specimens and those from other world regions indicates the absence of recent gene flow of leafminer flies from Brazil with specimens from Americas and Old world. The exception is L. brassicae, which exhibits one haplotype shared among Brazil, Philippines and Sri Lanka. The host range identification and geographical isolation of leafminer fly species from Brazil comprise useful information for quarantine and pest management purposes.