Influência de épocas de plantio, inseticidas e população de plantas sobre pragas e rendimento do arroz de sequeiro

The influence of four planting dates (Oct. 20, 1987; Nov. 17, 1987; Dec. 21, 1987 and Jan. 14, 1988), three seeding rates (32, 54 and 75 seeds/m) and five insecticides (carbofuran 50 G, furathiocarb 666 TS, carbofuran 350 TS, thiodicarb 350 TS e deltamethrin 25 CE) was evaluated on insect damage and grain yield of the upland rice cultivar IAC-47. In overall, the percentage of dead culms caused by Deois flavopicta, Elasmopalpus lignosellus and underground termites ranged from 5.4% to 24.3% and grain production was between 500 and 2,317 kg/ha. Planting in November appeared to be the most efficient procedure to reduce insect damage and attain maximum grain yield. Gain obtained from insecticide applications was greater when rice was planted in October, but it was considerably reduced in November. Association between carbofuran 50 G and the highest seeding rate was very important in reducing D. flavopicta populations for the earliest planting season.A influência de quatro épocas de plantio (20.10.87, 17.11.87, 21.12.87 e 14.01.88), três densidades de semeadura (32, 54 e 75 sementes/m) e cinco inseticidas (carbofuran 50 G, furathiocarb 666 TS, carbofuran 350 TS, thiodicarb 350 TS e deltamethrin 25 CE) sobre pragas e rendimento de grãos do arroz de sequeiro, foi estudada em experimento com a cultivar IAC-47. A porcentagem de colmos mortos por Deois flavopicta, Elasmopalpus lignosellus e cupins rizófilos nos plantios variou de 5,4% a 24,3% e a produção de grãos de 500 a 2.317 kg/ha. O plantio em 17.11.87 foi a principal medida para reduzir o dano das pragas e obter máximo rendimento de grãos (2.317 kg/ha). A vantagem do uso de inseticidas no plantio de 20.10.87 foi muito grande, mas diminuiu consideravelmente no plantio de 17.11.87. Associação do carbofuran 50 G com a maior densidade de semeadura foi muito importante para reduzir as populações de D. flavopicta no primeiro plantio

First reported occurrence of Helicoverpa armigera (Hübner)(Lepidoptera: Noctuidae) in Brazil

In this study is reported the first occurrence, in Brazil, of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), which was considered up till now a quarantine pest. The notification occurred in the Goiás State, in soybean; Bahia State, in volunteer soybean; and Mato Grosso State, in cotton

First record of the soybean stem fly Melanagromyza sojae (Diptera: Agromyzidae) in the Brazilian Savannah

The soybean stem fly [Melanagromyza sojae (Diptera: Agromyzidae)] is a pest widely distributed in the Asian continent. In Brazil, its occurrence has been reported since the 1980s, but it had not been reported in Brazilian Savannah areas yet. This is the first record of M. sojae in this region of great importance for the soybean world production. Specimens of the soybean stem fly were collected in a volunteer soybean area, in April 2018, in the Goiás state, Brazil, and sent for molecular identification. The similarity index of the collected specimens with M. sojae was higher than 99 %, thus confirming the identification of the species. The infestation level in the collection area was approximately 100 % of plants with damage caused by this insect. In Brazil, the occurrence of M. sojae, up to the present time, had been described as restricted to the southern states. This record raises the hypothesis that M. sojae is widespread in other agricultural areas of the Brazilian Savannah, and that its dissemination is favored by the maintenance of volunteer soybean

DESEMPENHO DO BICO HIDRÁULICO BOOMJET 5880-3/4-2TOC20 EM APLICAÇÕES DE HERBICIDA SOBRE Urochloa decumbens PERFORMANCE OF THE BOOMJET 5880-3/4-2TOC20 HYDRAULIC NOZZLE FOR HERBICIDE APPLICATION ON Urochloa decumbens (STAPF) R. WEBSTER

<!-- @page { margin: 2cm } --> <p class="western" align="justify">O experimento foi conduzido na região do cerrado no município de Goiânia, GO. Objetivou-se estudar a uniformidade de deposição das gotas de pulverização produzidas pelo bico hidráulico Boomjet 5880-3/4-2TOC20, com faixas operacionais de 10 m, 12 m e 14 m e aplicações realizadas a 1,0 m, 1,3 m e 1,5 m de altura em relação ao topo das plantas a serem dessecadas. Para avaliação dos tratamentos mediram-se as variáveis densidade de gotas (gotas.cm<sup>-2</sup>) e controle de plantas de <em>Urochloa decumbens</em> (Stapf) R. Webster. A simulação matemática da sobreposição das faixas de aplicação nos dois sentidos, unidirecional e bidirecional, mostraram elevada desuniformidade de deposição das gotas pulverizadas, estatisticamente representada por coeficientes de variação que variaram de 61,46% a 98,91%. Valores reduzidos referentes à densidade de gotas foram obtidos em pontos específicos da faixa de aplicação. Em pulverizações de glyphosate, o estudo mostrou controle satisfatório ao se adotar larguras de faixas de 10 m e 12 m, com o bico posicionado nas três alturas de aplicação estudadas.</p> <p class="western" align="justify">PALAVRAS-CHAVE: Plantas daninhas; plantio direto; pastagem.</p><!-- @page { margin: 2cm } --> <p class="western" align="justify">The experiment was carried out in the cerrado region of Goiânia, Goiás State, Brazil. The objective was to study the uniformity of drop deposition from spraying of the hydraulic Boomjet 5880-3/4-2TOC2095 nozzle in operation bands of 10 m, 12 m, and 14 m, and applied at 1.0 m, 1.3 m, and 1.5 m above plant tops. For treatment evaluation the variables drop density (droplets.cm<sup>-2</sup>) and control of Urochloa decumbens (Stapf) R. Webster plants were measured. The mathematical simulation of the overlapping bands application in both directions, unidirectional and bidirectional, showed low sprayed drop deposition uniformity, statistically represented by variation coefficients ranging from 61.46 % to 98.91%. Low values for drop density were obtained at specific points of the application band. Glyphosate applications at the three-studied nozzle application heights showed satisfactory control with operations bands of 10 m and 12 m.</p> <p class="western">KEY-WORDS: Weeds; agrochemical; no-tillage; pasture.</p&gt

The Potential Distribution of Invading <i>Helicoverpa armigera</i> in North America: Is It Just a Matter of Time?

<div><p><i>Helicoverpa armigera</i> has recently invaded South and Central America, and appears to be spreading rapidly. We update a previously developed potential distribution model to highlight the global invasion threat, with emphasis on the risks to the United States. The continued range expansion of <i>H</i>. <i>armigera</i> in Central America is likely to change the invasion threat it poses to North America qualitatively, making natural dispersal from either the Caribbean islands or Mexico feasible. To characterise the threat posed by <i>H</i>. <i>armigera</i>, we collated the value of the major host crops in the United States growing within its modelled potential range, including that area where it could expand its range during favourable seasons. We found that the annual value of crops that would be exposed to <i>H</i>. <i>armigera</i> totalled approximately US$78 billion p.a., with US$843 million p.a. worth growing in climates that are optimal for the pest. Elsewhere, <i>H</i>. <i>armigera</i> has developed broad-spectrum pesticide resistance; meaning that if it invades the United States, protecting these crops from significant production impacts could be challenging. It may be cost-effective to undertake pre-emptive biosecurity activities such as slowing the spread of <i>H</i>. <i>armigera</i> throughout the Americas, improving the system for detecting <i>H</i>. <i>armigera</i>, and methods for rapid identification, especially distinguishing between <i>H</i>. <i>armigera</i>, <i>H</i>. <i>zea</i> and potential <i>H</i>. <i>armigera</i> x <i>H</i>. <i>zea</i> hybrids. Developing biological control programs, especially using inundative techniques with entomopathogens and parasitoids could slow the spread of <i>H</i>. <i>armigera</i>, and reduce selective pressure for pesticide resistance. The rapid spread of <i>H</i>. <i>armigera</i> through South America into Central America suggests that its spread into North America is a matter of time. The likely natural dispersal routes preclude aggressive incursion responses, emphasizing the value of preparatory communication with agricultural producers in areas suitable for invasion by <i>H</i>. <i>armigera</i>.</p></div

The known global distribution of <i>Helicoverpa armigera</i>.

<p>Source GBIF and Matthews [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119618#pone.0119618.ref013" target="_blank">13</a>] (point location records), AgroAtlas (<a href="http://www.agroatlas.ru/en/content/pests/Helicoverpa_armigera/map/" target="_blank">http://www.agroatlas.ru/en/content/pests/Helicoverpa_armigera/map/</a>) for sub-regional mapping, CABI and Alejo Costa (Syngenta, pers. comm.), Cecilia Czepak (Universidade Federal de Goiás, pers. comm.) and Miguel F. Soria (IMAmt, Mato Grosso Cotton Institute, pers. comm.) for country or state level records. Where point location records were available, coarser level records have been ignored. Categories such as ‘widespread’ should be interpreted cautiously. For example, in Northern Africa it may only be widespread throughout the very restricted cropping areas adjacent to the Mediterranean Sea or inland irrigation areas.</p

The invasion threats to North America by <i>Helicoverpa armigera</i>.

<p>South American locations known to be infested by <i>H</i>. <i>armigera</i> are indicated by red polygon outlines. Cropping areas in Central and South America suitable for establishment (EI positive under appropriate irrigation and natural rainfall scenarios) are indicated in pale green. In North America, areas suitable for establishment are indicated in dark green. Areas suitable for seasonal migration-based impacts are indicated in bright green.</p

Weekly Growth Index values (Major Y-axis) and various measures of population abundance for <i>Helicoverpa armigera</i> (expressed as a % of the total catch, secondary Y-axis) over a year (time in weeks, 1–52) from 1 January.

<p>The GI_W (thick solid line) is an average of 4 CLIMEX scenarios for <i>H</i>. <i>armigera</i> (with and without irrigation and with and without diapause) for: (a) Urumqui, Xinjiang province (China) where the two thinner lines are light trap catches in two agricultural landscapes [Aksu county (40° 56’N, 80°27’E) and Maigeiti county (38°53’N, 77°37’E)] [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119618#pone.0119618.ref071" target="_blank">71</a>], (b) Ludhianna (India) where the thinner dashed line is pheromone trap catch of males (V. Dilawari, unpublished data) and (c) Narrabri (Australia) where the solid thin line is for average light trap catches (from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119618#pone.0119618.ref035" target="_blank">35</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119618#pone.0119618.ref046" target="_blank">46</a>]), and the remaining lines are for male light-trap catch (dashed line) and pheromone trap catch (fine dashed line) (from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0119618#pone.0119618.ref072" target="_blank">72</a>]).</p