Regiane Cristina Oliveira de Freitas Bueno

Releasing number of Telenomus remus (Nixon) (Hymenoptera: Platygastridae) against Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in corn, cotton and soybean

Telenomus remus releasing numbers may vary depending on the crop, plant architecture and/or the plant phenological stage. Thus, we examined the number of parasitoids needed for effective pest control of Spodoptera frugiperda on corn, cotton and soybean. In all crops, the parasitism response in relation to increasing numbers of the parasitoids had a quadratic effect. In corn, the maximum parasitism observed was 99.8% and 96.8% at a parasitoid releasing number of 0.231 and 0.264 T. remus females per S. frugiperda egg at phenological stages V4 and V10, respectively. Differently, in cotton and soybean, the highest parasitim were recorded using the highest tested T. remus releasing numbers (0.297 parasitoid per S. frugiperda egg). In cotton, it was 77.8% and 73.1% at the vegetative and reproductive stages, respectively and in soybean, it was 77.3% and 54.4% also at the vegetative and reproductive stages. Thus, the appropriated T. remus releasing number might vary accordingly to the crop and plant phenological stage, being higher for soybean and cotton and lower for corn.

Occurrence of Helicoverpa armigera (Hübner, 1808) on citrus in the state of Sao Paulo, Brazil

The occurrence of Helicoverpa armigera (Hubner, 1808) was first reported in citrus orchard in the state of Sao Paulo (SP). High infestation levels of H. armigera were observed in October 2012, in the city of Botucatu, SP. The larvae was fed of all parts of the plants. The injuries on the leaves caused drastic reduction in the leaf area and the fruits attack occurred from an early stage of development to the ripe fruit. Thus, the first occurrence of H. armigera in this citrus culture adds to the list of hosts of this pest, and is of great importance, because it confirms H. armigera potential dispersion and polyphagia.

Different timing of whitefly control and soybean yield

Experimentos foram conduzidos em Parauna, Goias, Brasil, avaliando o impacto da mosca-branca na producao de soja. O delineamento experimental foi em blocos ao acaso, com quatro tratamentos e quatro repeticoes (10m x 20m). Os tratamentos foram diferentes niveis de infestacao, obtidos pela aplicacao de inseticidas em diferentes momentos; a testemunha foi mantida livre do ataque da praga, aplicando-se inseticida semanalmente. O numero de insetos por foliolo foi avaliado semanalmente e, na colheita, foi avaliada a produtividade (kg ha-1) e o peso de 100 sementes (g). A soja foi tolerante a mosca-branca, visto que apenas o tratamento em que as ninfas por foliolo atingiram a media de 136,31±26,60 (tratamento sem aplicacao de inseticidas) foi severo o suficiente para causar perdas de produtividade. Essa perda foi provavelmente associada a formacao de fumagina, causada pelo fungo Capnodium sp., que se desenvolve nas secrecoes acucaradas produzidas pela mosca-branca na superficie das folhas. Portanto, inseticidas precisam apenas ser aplicados quando a infestacao de mosca-branca for severa o suficiente para propiciar a formacao de fumagina. Entretanto, a relacao entre o numero de insetos por foliolo e a formacao de fumagina ainda precisa ser determinada para diferentes cultivares, assim como para diferentes condicoes ambientais.

Telenomus remus (Hymenoptera: Platygastridae) Parasitism on Eggs of Anticarsia gemmatalis (Lepidoptera: Eribidae) Compared With Its Natural Host Spodoptera frugiperda (Lepidoptera: Noctuidae)

ABSTRACT The capacity of Telenomus remus to parasitize eggs of Anticarsia gemmatalis, compared with its natural host, Spodoptera frugiperda, was evaluated under different temperatures. The parasitoid T. remus was reared at 25 ± 1°C for a single generation on both hosts. After reaching the adult stage, they were allowed to parasitize both hosts to study parasitoid biology and parasitism capacity at temperatures between 19°C and 37 ± 1°C. Egg-to-adult developmental time was similar on both hosts. The number of A. gemmatalis eggs parasitized was lower than that of S. frugiperda eggs at all temperatures. Parental female longevity of parasitoids was greater on A. gemmatalis eggs. This indicated a smaller metabolic expense during parasitism, acommonfeature observed on nonpreferable hosts. In general, sex ratio was little affected by temperature or hosts. When parental T. remus were reared on A. gemmatalis before the experiment, base temperature (Tb) and the thermal constant (K) were 9.53°C and 209.57 DD on eggs of A. gemmatalis and 9.68°C and 197.79 DD on eggs of S. frugiperda, respectively. When parental T. remus were reared on S. frugiperda eggs, Tb and K were 10.12°C and 188.46 DD and 9.69°C and 190.24 DD for the evaluated host eggs of A. gemmatalis and S. frugiperda, respectively. Therefore, T. remus develops in eggs of A. gemmatalis. This can be beneficial for its use in field crops where outbreaks of both Spodoptera spp. and A. gemmatalis occur. However, A. gemmatalis is a less favorable host for the parasitoid development.

Distribution and phylogenetics of whiteflies and their endosymbiont relationships after the Mediterranean species invasion in Brazil

The Bemisia tabaci is a polyphagous insect and a successful vector of plant viruses. B. tabaci is a species complex and in Brazil native species from the New World (NW) group, as well as the invasive species, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) were reported. For better understanding the distribution of the different species four years after the Mediterranean species invasion in Brazil, whiteflies were collected from 237 locations throughout the country between the years of 2013 and 2017, species were identified and the facultative endosymbionts detected. The survey revealed that MEAM1 was the prevalent species found on major crops across Brazil. It is the only species present in North, Northwestern and Central Brazil and was associated with virus-infected plants. MED was found in five States from Southeast to South regions, infesting mainly ornamental plants and was not associated with virus-infected plants. The prevalent endosymbionts identified in MEAM1 were Hamiltonella and Rickettsia; and the mtCOI analysis revealed low genetic diversity for MEAM1. In contrast, several different endosymbionts were identified in MED including Hamiltonella, Rickettsia, Wolbachia and Arsenophonus; and two distinct genetic groups were found based on the mtCOI analysis. Monitoring the distribution of the whiteflies species in Brazil is essential for proper management of this pest.

Thermal requirements, development and number of generations of Duponchelia fovealis (Zeller) (Lepidoptera: Crambidae)

In this study, the effect of temperature on the growth of the European pepper moth, Duponchelia fovealis (Zeller), was assessed at five constant temperatures (18, 21, 24, 27 and 30 °C). The European pepper moth was observed to complete its developmental stages (from egg to adult) at all the temperatures evaluated. From the results, it was evident that temperature affected the rate and development time of all the growth stages, to a significant degree. The length in time of the embryonic, larval, pupal and total (egg-adult) stages was observed to drop as the temperature rose from 18 to 24 °C, but remained constant between 27 and 30 °C. The developmental time in the pre-pupal stage dropped between 18 and 30 °C. The European pepper moth takes 454 degree-days to complete development at 11.7 °C temperature threshold. The D. fovealis survival was thus inversely proportional to temperature over range of 18 to 30 °C. On assessing the number of annual generations for the five largest strawberry-producing municipalities in Espírito Santo State, an average of 5.5 generations per year was estimated. This is a first report of temperature on D. fovealis development.

Ocorrência de mosca-branca em Annona squamosa no estado de São Paulo

In Brazil the knowledge about the geographical distribution and host plants of whiteflies (Hemiptera: Aleyrodidae) is limited, mainly on crops. In this communication, the occurrence of Aleurodicus mirabilis (Cockerell, 1898) in high infestations in custard apple (Annona squamosa Linnaeus, 1753) is recorded in the state of Sao Paulo, Brazil.