Ricardo Antonio Polanczyk

Immunity of an Alternative Host Can Be Overcome by Higher Densities of Its Parasitoids Palmistichus elaeisis and Trichospilus diatraeae

Interactions of the parasitoids Palmistichus elaeisis Delvare & LaSalle and Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) with its alternative host Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) affect the success or failure of the mass production of these parasitoids for use in integrated pest management programs. The aim of this study was to evaluate changes in the cellular defense and encapsulation ability of A. gemmatalis pupae against P. elaeisis or T. diatraeae in adult parasitoid densities of 1, 3, 5, 7, 9, 11 or 13 parasitoids/pupae. We evaluated the total quantity of circulating hemocytes and the encapsulation rate versus density. Increasing parasitoid density reduced the total number of hemocytes in the hemolymph and the encapsulation rate by parasitized pupae. Furthermore, densities of P. elaeisis above 5 parasitoids/pupae caused higher reduction in total hemocyte numbers. The encapsulation rate fell with increasing parasitoid density. However, parasitic invasion by both species induced generally similar responses. The reduction in defensive capacity of A. gemmatalis is related to the adjustment of the density of these parasitoids to their development in this host. Thus, the role of the density of P. elaeisis or T. diatraeae by pupa is induced suppression of cellular defense and encapsulation of the host, even without them possesses a co-evolutionary history. Furthermore, these findings can predict the success of P. elaeisis and T. diatraeae in the control of insect pests through the use of immunology as a tool for evaluation of natural enemies.

Effect of the insect growth regulator diflubenzuron on the predator Podisus nigrispinus (Heteroptera: Pentatomidae)

Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is a common natural predator of defoliating caterpillars in agricultural and forest systems. Insecticides acting as growth regulators of insect pests can indirectly affect their predators through consumption of contaminated prey. We examined the reproductive performance of P. nigrispinus fed on caterpillars of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) reared on soybean leaves exposed to the chitin synthesis inhibitor, diflubenzuron. Caterpillars of A. gemmatalis were fed for 12xa0h with treated soybean leaves and offered to adults of the predator P. nigrispinus over five consecutive days. The fertility of P. nigrispinus was reduced when feeding on diflubenzuron treated caterpillars, especially at the beginning of the reproductive period, but recovered 3xa0weeks later. The effects of diflubenzuron ingestion on the life table parameters of P. nigrispinus included an increase in the period taken to double the population size, and reductions in the intrinsic rate of population increase, generation duration, and net reproductive rate. Diflubenzuron therefore had an indirect negative effect on the reproduction and the population dynamics of the non-target predator P. nigrispinus. Clearly, its use in integrated pest management requires further evaluation.

Associação do óleo de mamona com Beauveria bassiana no controle da traça-das-crucíferas

Abstract – The objective of this work was to evaluate the efficiency,the stability, the application mode and the compatibility between castor bean oil and the entomopathogenic fungus Beauveria bassiana , for diamondback moth ( Plutella xylostella ) control. In the firstexperiment, the efficiency,the stability after 70 days of storage, and the application mode of castor bean oil were evaluated. In the second one, the compatibility of castor bean oil with B. bassiana was evaluated. The insecticidal activity of the castor bean oil is unstable over time. The castor bean oil is compatible with B. bassiana against P. xylostella .Index terms: Beauveria bassiana , Plutella xylostella , Ricinus communis , entomopathogenic fungus. A traca‑das‑cruciferas, Diaphania nitidalis Plutella xylostella (L.) (Lepidoptera: Plutellidae), e a praga mais importante de plantas da familia Brassicaceae. Para o seu controle, utilizam-se basicamente inseticidas (Castelo Branco & Medeiros, 2001). No entanto, outros metodos para o controle desta praga tambem devem ser avaliados, entre os quais, a utilizacao de fungos entomopatogenicos, como

Ocorrência de Trichospilus diatraeae (Hym.: Eulophidae) em broca-das-cucurbitáceas, no Brasil

This study aims to record the first occurrence in Brazil of the parasitoid pupae Trichospilus diatraeae (Cherian & Margabandhu, 1942) (Hymenoptera: Eulophidae) on the melonworm, Diaphania hyalinata (L.) (Lepidoptera: Pyralidae). The specie T. diatraeae has been reported in pests of the soursop in the Distrito Federal, Brazil and eucalyptus in the Brazilian States of Minas Gerais and Sao Paulo. In the production system of pumpkin D. hyalinata is recognized as a significant pest which causes serious losses as a result of injuries caused in different parts of the plant. The occurrence of the parasitoid was recorded in pupae collected in the field, located on the campus of the Center of Agrarian Sciences, Federal University of Espirito Santo, Alegre Espirito Santo State, Brazil.

Potential of Entomopathogenic Fungi as Biological Control Agents of Diamondback Moth (Lepidoptera: Plutellidae) and Compatibility With Chemical Insecticides

Abstract The objectives were to evaluate the efficiency of entomopathogenic fungi against Plutella xylostella (L.) and the compatibility of the most virulent isolates with some of the insecticides registered for use on cabbage crops. Pathogenicity tests used isolates of Beauveria bassiana, Metarhizium rileyi, Isaria fumosorosea, Isaria sinclairii, and Lecanicillium muscarium standardized at a concentration of 107 conidia/ml. Cabbage leaf discs were immersed in these suspensions, and after evaporation of the excess water, were placed 10 second-instar larvae of P. xylostella, totaling 10 leaf discs per treatment. Mortality was assessed 7 d after treatment, and the isolates that caused mortality >80% were used to estimate LC50 and LT50. The compatibilities of the most virulent isolates and the insecticides were tested from the mixture of these into the culture medium, and after solidifying, the medium was inoculated with an aliquot of the isolated suspension. The following parameters were evaluated: growth of the colony, number and viability of conidia after 7 d. The isolated IBCB01, IBCB18, IBCB66, and IBCB87 of B. bassiana, LCMAP101 of M. rileyi, and ARSEF7973 of I. sinclairii caused mortality between 80 and 100%, with LC50 and LT50 between 2.504 to 6.775 × 104 conidia/ml and 52.22 to 112.13 h, respectively. The active ingredients thiamethoxam and azadirachtin were compatible with the entomopathogenic fungi. The results suggest that the use of these isolates is an important alternative in the pesticidal management of P. xylostella, with the possible exception of the associated use of chemical controls using the active ingredients thiamethoxam or azadirachtin.

Interactions of Bacillus thuringiensis bioinsecticides and the predatory stink bug Podisus nigrispinus to control Plutella xylostella

The diamondback moth (DBM), Plutella xylostella (L.), is a major pest of brassica crops worldwide. Control of this pest is difficult because it rapidly develops resistance to synthetic and biological insecticides and because of the effects of insecticides on its natural enemies. Podisus nigrispinus (Dallas) is a predator that feeds on its prey, as well as on the host plants of its prey, and is an important biological control agent of DBMs. The aim of this study was to determine the susceptibility of P. xylostella larvae to two bioinsecticides: the HD1 strain of Bacillus thuringiensis (B. thuringiensis var. kurstaki) and the commercial product Agree® (B. thuringiensis var. aizawai CG 91). In addition, the impact of these bioinsecticides on the P. nigrispinus consumption of DBM larvae and phytophagy was evaluated. Both the HD1 strain and Agree® caused 100% mortality in P. xylostella larvae. P. nigrispinus nymphs fed only with kale leaves (Brassica oleracea var. acephala) sprayed with water, the HD1 strain, or Agree® did not complete their nymphal development. When prey was also available, P. nigiripinus fed on kale leaves to obtain water. Both nymphs and adults of P. nigrispinus consumed greater numbers of DBM larvae, and fed less on kale leaves, when sprayed with the HD1 strain or Agree®. These results suggest a positive interaction of B. thuringiensis‐based products and the predator P. nigrispinus in the control of P. xylostella larvae.

Interactions between the entomopathogenic fungi Beauveria bassiana (Ascomycota: Hypocreales) and the aphid parasitoid Diaeretiella rapae (Hymenoptera: Braconidae) on Myzus persicae (Hemiptera: Aphididae).

ABSTRACT n The interactions between the entomopathogenic fungus Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Ascomycota: Hypocreales) and the aphid parasitoid Diaeretiella rapae McIntoch (Hymenoptera: Braconidae) were evaluated under laboratory conditions. Nymphs of Myzus persicae Sulzer (Hemiptera: Aphididae) were first exposed to parasitoid females for 24 h and then 0, 24, and 48 h afterwards sprayed with a solution of B. bassiana. Likewise, aphids were also sprayed with B. bassiana and then exposed to parasitoids at 0, 24, and 48 h afterwards. Parasitism rate varied from 13 to 66.5%, and were significantly lower in treatments where the two agents were exposed within a 0 -24 h time interval compared with the control (without B. bassiana). Parasitoid emergence was negatively affected in treatments with B. bassiana spraying and subsequent exposure to D. rapae. Decreases in longevity of adult females of the D. rapae F1 generation were observed in treatments with B. bassiana spraying. The application of these two biological control agents can be used in combination on the control of M. persicae, wherein this use requires effective time management to avoid antagonistic interactions.

Parâmetros biológicos e tabela de vida de Tetranychus urticae (Acari: Tetranychidae) em cultivares de mamão

The study was conducted to evaluate the Tetranichus urticae development and reproduction in commercial Carica papaya cultivars. The assayed cultivars belongs to the Formosa (Tainung 01 and Calimosa) and from the Solo (Golden and Sunrise) groups. A fertilized female was transferred to a leaf dish (n=50 repetitions) and was removed after a period of 12 hours and evaluations were done every 12 hours recording the incubation period, length of immature stage, longevity and fecundity of adults and viability of these stages. The cultivars of papaya, Tainung 01, Calimosa, Sunrise and Golden are adequate hosts for T. urticae. The recorded viability above 90% was not influenced by the different cultivars during all the development phases. There was not statistic difference among the cultivars in the parameters: pre-ovopositional period, and egg viability. Mites assayed in Tainung 01 cultivar showed a shorter duration of the egg, larva, protonymph and egg-adult. At life table parameters and fertility, presented smaller Ro, rm and λ, and larger Td. Sunrise is the cultivar most adequate for T. urticae development, considering that mites assayed in this cultivar showed a larger production of eggs per female, longer female longevity, and higher reproduction rate (larger Ro, rm and λ and smaller Td).

Efeito de beauveria bassiana (bals.) Vuillemin e Metarhizium anisopliae (metsch.) sorokin nos parâmetros biológicos de trichogramma atopovirilia oatman & platner, 1983 (hymenoptera: trichogrammatidae)

Dois experimentos foram realizados para avaliar o efeito de duas formulacoes comerciais a base de Beauveria bassiana (Bals.) Vuillemin e Metarhizium anisopliae (Metsch., Sorokin sobre os parâmetros biologicos de Trichogramma atopovirilia Oatman & Platner, 1983. No primeiro experimento, cartelas com ovos de Spodoptera frugiperda, 1797 foram mergulhadas em suspensoes preparadas com os produtos e, em seguida, colocadas a disposicao dos parasitoides para oviposicao, durante um periodo de 24 horas. No segundo, femeas do parasitoide foram alimentadas com uma solucao mel e suspensao de conidios. Em ambos os experimentos as femeas mortas foram colocadas em uma câmara umida para observar a esporulacao dos fungos. Os tratamentos foram mantidos em câmara climatizada com temperatura de 25±1o C, umidade relativa de 70±10% e fotofase de 14 horas. Avaliou-se a longevidade e mortalidade dos adultos, indice de parasitismo, emergencia do parasitoide, numero de individuos por ovo e razao sexual dos descendentes. As formulacoes nao interferiram nos parâmetros avaliados e nao foi observada a esporulacao do fungo no cadaver do parasitoide adulto. E possivel inferir que T. atopovirilia e os fungos entomopatogenicos B. bassiana e M. anisopliae sao compativeis e podem ser empregados simultaneamente em programas de manejo integrado de S. frugiperda.

Bacillus thuringiensis – Based Biopesticides Against Agricultural Pests in Latin America

Twenty years after its discovery, the first attempts to use the entomopathogenic bacterium Bacillus thuringiensis (Bt) to control pests were made in Europe. Due to the successes achieved in some laboratory trials, commercial production of this pathogen began in France, where commercial formulations entered the market in 1938 as the product Sporeine. In the U.S., the use of this pathogen increased after 1950, mainly for the control of lepidopteran pests, resulting in the production of a formulation called Thuricide (Beegle & Yamamoto, 1992; Peferoen & Lambert, 1992; Lord, 2005).