In the present study, another species frequently observed was F. schultzei (> 83%) (Table 1). It was observed mainly in the regions with large commercial cotton cultivation areas, such as Alcinópolis, Chapadão do Sul, Costa Rica, and Sidrolândia. Furthermore, F. schultzei was overabundant in the municipalities of Sidrolândia and Costa Rica. A common feature of these two municipalities was the use of insecticides creating a shock effect on the cottoncrop residue, and no physical methods were followed. Therefore, insect pests with a high fertility rate and short life cycle were able to recover rapidly in this environment, as observed in A. gossypii, B. tabaci, and F. schultzei. These insects exhibited the highest faunal index values in the municipalities studied (Gallo et al., 2002; Campos et al., 2009; Funichello et al., 2012).
Cotton seeds were sown in January 2016, spaced at 0.80 m between rows, as a second crop (succession to beans), totaling a population of one hundred thousand plants per hectare. Sowing fertilization did not include micronutrients and consisted of 15 kg ha -1 of nitrogen and 81 kg ha -1 of phosphorus (on furrow) and 90 kg ha -1 of potassium chloride (top dressed previously on sowing). At 20 days after emergence (DAE), 22 kg ha -1 of nitrogen was applied as top-dressing. The other agricultural inputs were applied throughout plant development by the monitoring and standards for pests and diseases control in the region (FREIRE, 2015).
According to YAMASHITA et al. (2008), controlling lim- iting factors such as weeds is fundamental, so that the crop can express its full productive potential. Since weeds compete for water, light and nutrients, the cotton must remain free of these plants for a good part of its cycle in order to avoid weed com- petition, the proliferation of pests and diseases and to guaran- tee the quality of the plume produced (CHRISTOFFOLETI et al., 2011). Inadequate weed management can lead to losses in income greater than 90% (RAIMONDI et al., 2014). During the cotton cycle, weeds not only compete for environ- mental resources (water, light and nutrients), but also alter- native hosts for viruses and various pest arthropods capable of attacking this crop. Sida rhombifolia (arrowleaf sida) and Scaphyglottis micrantha (orchid) species host the virus that causes the common mosaic virus (Abutilon mosaic virus) transmit- ted by the Bemisia tabaci biotype B whitefly (SUASSUNA; COUTINHO, 2015).
For the experiment conducted in Bahia, the cultivars FM 940 GLT, FM 980 GLT, and FM 913 GLT were planted on 30 December 2013. For the experiment in Mato Grosso, the varieties FM 940 GLT and FM 980 GLT were planted on 14 December 2013. The FM 940 GLT variety is characterized as high growth and medium cycle, and FM 980 GLT of long cycle. The FM 913 GLT variety is characterized by early blooming and average growth rate. Cotton with GLT technology have genes derived through genetic transfer that confer the plants defense against pests in the Lepidoptera order, as well as tolerance to the herbicides glufosinate-ammonium and glyphosate, which aid in plant health management of the crop. All varieties were sown at the same time to provide similar climatic conditions during the cycle. A summary of the rainfall and average temperature during the experiments is provided in figure 1.
We describe the vertical and horizontal distribution of the cotton aphid Aphis gossypii Glover within a cotton plant in two cotton (Gossypium hirsutum Linnaeus) cultivars (BRS Safira and BRS Rubí) with colored fiber over the time. Measurements of aphid population dynamics and distribution in the cotton plants were recorded in intervals of seven days. The number of apterous or alate aphids and their specific locations were recorded, using as a reference point the location of nodes on the mainstem of the plant and also those on the leaves present on branches and fruit structures. The number of apterous aphids found on the cultivar BRS Safira (56,515 aphids) was greater than that found on BRS Rubí (50,537 aphids). There was no significant difference between the number of alate aphids found on the cultivars BRS Safira (365 aphids/plant) and BRS Rubí (477 aphids/ plant). There were interactions between cotton cultivar and plant age, between plant region and plant age, and between cultivar and plant region for apterous aphids. The results of this study are of great importance in improving control strategies for A. gossypii in the naturally-colored cotton cultivars BRS Safira and BRS Rubí. Key words: Aphis gossypii, behavior, cotton with colored fibers, distribution.
The primary goal of the developed system has been to identi- fy the existence of pathogens in cotton foliars. Once a disease is identified it has to be automatically classified through further processing of the corresponding image. The pathogens used in our tests are among those most frequently occurring in Brazil, which are very aggressive, rapidly spreading throughout the plantations, and that can be fought against only by the use of chemicals [1, 2, 3, 4]. Three diseases were used during the clas- sification stage, as follows: Ramularia (RA), Bacterial Blight (MA), and Ascochyta Blight (AS). Alternatively we allowed the system to classify an image as not belonging to any of these classes (NONE).
Although presenting residual effects for P. nigrispinus nymphs, a single application of thiamethoxam and imidacloprid at rate of 1 mg (a.i.) per plant was enough to control immature whitefly population on cotton plants in potted plants and suppress whitefly and aphid colonization on plants in the field (Figs. 2 and 3). Although with shorter residual effect against whitefly colonization compared to higher doses, thiamethoxam at rate of 0.5 mg (a.i) per plant showed potential of use and should be better studied. Lower pest exposure to thiamethoxam and imidacloprid residues by single application and shorter residual contact in each cotton season should be considered within a cotton pest management program. This strategy reduces the selection pressure on whitefly and on other pests for resistance extending the insecticide lifespan, and also seems less harmful to the heteropteran predators due to shorter residual effects. Moreover, extended residual effects of the systemic insecticides, including neonicotinoids, have been claimed as a major cause for resistance selection on whitefly populations (Elbert & Nauen 2000, El Kady & Devine 2003).
Shoot length was significantly affected by MC, with a linear decline and a total decrease of 79.5% when compared with the control (Figure 1). Nagashima et al. (2005) found similar results when cotton seeds were soaked in MC, and this effect was observed until 49 days after emergence. In later work, Nagashima et al. (2007) observed that soaking cotton seeds in an MC solution resulted in a linear reduction in plant height in the first weeks of growth (26.1% less than the control at a dose of 7.5%). Athayde and Lamas (1999) also reported a decrease in cotton height and a result similar to that of Zhao and Oosterhuis (2000) was observed until 21 days after sowing even though MC was sprayed on cotton leaves rather than seeds, as in the present study. Teixeira et al. (2008) also reported significant differences in cotton plant height, cultivar FMX 986, when MC was used in the leaves, and according to the authors, this effect could be attributed to the anti-gibberellin effect of the product. Yeates et al. (2005) also observed shorter plant when the seed surfaces were treated with MC.
The use of preemergent herbicide with residual soil activity has become common practice in cotton crops (Troxler et al., 2002) since in recent years there has been considerable progress in biotypes number of weeds resistant to glyphosate in cotton fields; currently the biggest problem is in the biotypes presenting multiple resistance to EPSPs (5- enolpyruvylshikimate 3-phosphate synthase) and ALS (acetolactate synthase enzyme) enzymes inhibitors, which has reduced the traditionally used selective latifolicide mixtures options for postemergence control. Consequently, the use of residual herbicides has become an important tool for weed control in cotton plants (Stephenson IV et al., 2004; Everman et al., 2009). Additionally, preemergence application in cotton plants minimizes early interference of weeds (Raimondi et al., 2014).
Net radiation (Rn) and soil heat flux (G) were directly measured using a net radiometer model NR-LITE (Kipp & Zonen, Delft, The Netherlands) installed 2 m above cotton canopy and two soil heat flux plates model HFP01 (Hukselfux Thermal Sensors, Delft, The Netherlands), one inter-row and other inter-plants, buried at 0.02 m soil depth, respectively. Dry and wet bulb temperatures were measured using psychrometers constructed with thermocouples type T (copper–constantan), installed at 0.5 and 2.0 m above canopy. The wind speed was measured at two heights (same heights of psychrometers) using 3-cup anemometer model 03101 (R.M. Young Copany, Traverse City, MI, USA). The height of psycrometers, anemometers, and net radiometer was adjusted weekly following the change in plant height. All these sensors were previously calibrated and connected to a CR3000 datalogger (Campbell Sci. Inc., Logan, UT). Data were sampled every 5 s, and 20-min averages were obtained and stored.
Perante a pandemia criada pelo COVID-19 muitas empresas tiveram a possibilidade de “entrar em lay-offxiv”. A Pure Cotton não foi exceção mas antes de o fazer terminou todas as encomendas que tinha em produção (evitando assim que os clientes reclamassem do atraso na entrega e cancelassem as encomendas). Nenhum cliente cancelou a encomenda e os clientes em perigo de fechar por causa do COVID, estavam cobertos pelo Seguro de Crédito. Para não parar a produção, neste período crítico, foram tomadas todas as medidas de segurança: medida da temperatura de todos os trabalhadores, desinfeção à entrada na empresa, separação de áreas de trabalho, uso obrigatório de mascaras e luvas, álcool-gel em vários locais da empresa, seleção de alguns funcionários para fazerem a ligação entre as diferentes áreas e a receção das visitas passou a ser feita na entrada da empresa. Depois de feitas todas as entregas (no final de Março), a Pure Cotton entrou em lay-off durante 4 semanas. “Foi muito duro. Mas o desespero inicial deu lugar a uma nova normalidade”, explica Ricki Madsen. A produção de máscaras comunitárias foi uma grande ajuda e reduziu os efeitos da pandemia em todo o setor têxtil - permitiu a continuidade do negócio dado que havia uma enorme procura por produtos de proteção por razões de saúde pública. Foi o surgimento de um novo mercado, completamente por explorar, com uma procura internacional enorme. Toda a gente tinha uma t-shirt mas ninguém tinha uma máscara. A Pure Cotton começou a produzir mascaras para clientes Alemães (80%), Franceses, e Holandeses – o mercado de excelência da empresa.
At the time of writing, only a few examples of insect- microorganism associations are eﬀectively being explored for control of pests or human diseases. This is still an open area of research with great potential for control of insect pests and vectors of disease, as the cases mentioned earlier using the paratransgenic strategy in the systems of sand- fly/leishmaniasis and sharpshooter/Pierce’s disease represent [ 50 – 52 ]. In fact, it is only recently that considerable infor- mation has been gathered to permit the design of alternative methods of control. Studies on diﬀerent bacterial groups, such as actinobacteria, reminds us how intricate and complex the associations between stink bugs and microorganisms are. Further comprehension of their biological, physiological, and ecological features is necessary to have a better picture
Although photosynthesis rates have been used to distinguish water deficit tolerant and sensitive genotypes in various species, including cotton (LEVI et al., 2009; SARANGA et al., 2004), procedures for measuring gas exchanges in photosynthetic analysis are laborious and impractical for use in a breeding program (EARL; TOLLENAAR, 1999). In studies with the barley crop, it was noted that the use of indirect and quick methods for determining photosynthetic activity, as well as the measuring of chlorophyll fluorescence, can identify genotypes that are tolerant and sensitive to water deficits and take less time when compared to that techniques for measuring gas exchanges (RONG-HUA et al., 2006). Other physiological traits, such as relative water content (RWC)
EREBP transcription factor is only found in plant, closely related with response to drought, high salt, low temperature, disease and plant development. Simultaneously it participates in many signal pathways, such as growth and development, disease and environment stress (Riechmann and Meyerowitz 1998). GhEREB2 gene was isolated from cotton (Gossypium hirsutum L.) with yeast one-hybrid system by Duan et al (2006). Its encoding protein has a highly conserved AP2/EREBP domain and other typical features of EREBP transcription factors. The cDNA sequence of GhEREB2 has been submitted to GenBank databases with GenBank accession numbers AY962571. In addition, GhEREB2 was expressed in the roots, stems and leaves of cotton, and expression of GhEREB2 were induced by ethylene and jasmonic acid, also slightly induced by stress conditions, such as drought and cold treatment. Further studies indicated that GhEREB2 might be involved as the positive transcription factor in biotic and abiotic stresses signal transduction pathways (Duan et al. 2006). In this work, the cDNA sequence of GhEREB2 was transferred to A. bidentata by Agrobacterium tumefaciens in order to establish a set of low-cost, adaptable and efficient genetic transformation system for A. bidentata and obtain some transgenic plants to provide germplasm resource for new cultivar breeding of A. bidentata.
As discussed, it is crucial to deine the breeding environment‑target, since the route to yield‑change expressed by crops is different for each geographical location and new growing season, relecting new combinations and temporal dynamics in the biotic and abiotic environments (Cooper et al., 1997; Chenu et al., 2011). Certainly, the DNA code may carry information that inluences alternate plant responses to each new environment, but the way information is integrated throughout the growing season is critically determinant for crop yield at the physiological level and across the community of plants (Rebetzke et al., 2013). In this sense, ield physiological evaluations of the germplasm performance for abiotic stress, as well as water and heat constraints are challenging. Field environments are unpredictable and genotype by environment interactions are dificult to interpret, if the environment target is not well characterized. As a result, there are limited breeding program advances, since that is a challenging bottleneck for a good ield screening to select for a speciic trait. The use of physiological traits such as Δ could help the breeding programs in the characterization of target environments, considering the performance of a certain genotype according to its interaction in each environment. The wide Δ variation shown by GO 05 809 genotype in both sites strongly supports the above argument, allowing breeders to select a genotype for each target environment, considering plant versus environment interactions for a speciic trait, such as better performance for water use Figure 4. Leaf area and root : shoot ratio attributes of selected
G. Cot. 100, G. Cot. 10, Narasimha, G. 247) and resultant forty four hybrids developed by line x tester mating design and these hybrids were evaluated with one standard check hybrid G. Cot. Hy. 12. The experimental material was sown in a randomized block design with three replications during kharif 2010-11 at Regional Research Station, Anand Agricultural University, Anand (Gujarat). A single row of 4.5 meter length was assigned to each genotype with 10 plants having 45 cm intra row spacing and 120 cm inter row spacing. Five plants were randomly selected from each replication for each genotype and the average value per plot was computed for recording observations on plant height, number of monopodia, number of sympodia, total number of bolls, seed cotton yield and seed index; whereas, average boll weight, ginning percentage, lint yield and lint index were calculated on formula basis. While, days to 50 per cent flowering was recorded on plot basis and oil content was estimated by NMR (Nuclear Magnetic Resonance) machine. Analysis of variance technique suggested by Panse and Sukhatme (1978) was followed to test the differences between the genotypes for all the characters under study. Heterosis was estimated in terms of two parameters, i.e. heterobeltiosis (Fonseca and Patterson, 1968) and standard heterosis (Meredith and Bridge, 1972). While, the dominance estimates was carried out as per following formula given by Griffing (1950) and Petr and Frey (1966).
All of us have our own concepts of how the world works and why certain things happen, every hypothesis that is tested has a conceptual model supporting it. Physical down-scaled representations (physical models) of the system have been used by engineers for a long time, but they are rarely used to represent biological systems, although it can be said that a plant in an experimental plot or container is a physical model of the crop in the field.
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Products used by people in their homes or in restaurants mainly contain compounds from the group of pyrethroids, for example deltamethrin, alphamethrin, tetramethrin. These are effective for controlling mosquitoes, flies, and other insects. Additionally, repellents or substances acting dissuasive on mosquitoes can be used to protest against their bites. The formulations used for insect are available in different forms, e.g., sprays, concentrates, powders, sticks. All pesticides are toxic to humans to some degree. However, the doses that are acutely toxic to humans are usually far higher than those required for killing vectors and pests. The key to safe use of pesticides is to reduce to a minimum the possibilities of unsafe exposure during handling of hazardous chemicals. Therefore, care in handling pesticides, particularly by spraying staff and persons living in sprayed houses, should be a routine practice and form an integral part of any program involving the application of pesticides (WHO, 2006; Sánchez-Bayo and Ortega, 2012).