Dinâmica populacional de afídeos do morangueiro : parâmetros de crescimento e estudo de comportamento alimentar de Chaetosiphon fragaefolii por epg(Electrical penetration graphs)

Orientador : Dr. Átila Francisco MógorCo-orientadoras : Profª Drª. Maria Aparecida Cassilha Zawadneak e Profª Drª. Susete do Rocio Chiarello PenteadoDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Agrárias, Programa de Pós-Graduação em Agronomia. Defesa: Curitiba, 24/02/2014Inclui referênciasÁrea de concentração: Produção vegetalResumo: Afídeos são pragas-chave do morangueiro, causando danos diretos e indiretos, principalmente devido à sucção continua de seiva e transmissão de vírus. Chaetosiphon fragaefolii é o principal afídeo associado ao morangueiro. O conhecimento da flutuação populacional da praga é fundamental para o estabelecimento de um manejo eficiente e racional. O uso de cultivares resistentes pode ser uma importante estratégia de controle de viroses transmitidas por afídeos. Estudos sobre resistência de plantas a insetos podem ser realizados por meio do monitoramento eletrônico (EPG). O presente trabalho objetivou registrar a flutuação populacional de afídeos do morangueiro, relacionando sua ocorrência com fatores climáticos e população de inimigos naturais; estudar em condições de laboratório os parâmetros biológicos e de crescimento populacional e o comportamento alimentar de C. fragaefolii em quatro cultivares de morangueiro. Durante o período de outubro de 2012 a julho de 2013, foram realizados monitoramentos quinzenais em área experimental de morangueiro em Pinhais, Paraná. Foram encontradas as seguintes espécies de afídeos: Chaetosiphon fragaefolii, Aphis forbesi e Aphis gossypii, sendo a primeira a espécie predominante. Os períodos de maior ocorrência a campo de C. fragaefolli e A. forbesi foram registrados nos meses de junho e julho de 2013. Para A. gossypii, o pico populacional foi no mês de março de 2013. Fatores climáticos afetaram significativamente a densidade populacional de afídeos, sendo que C. fragaefolli e A. forbesi apresentaram correlação negativa com a temperatura e A. gossypii apresentou correlação positiva. Os inimigos naturais mais encontrados foram coleópteros coccinelídeos, hemípteros predadores e himenópteros parasitoides. Nos experimentos de laboratório, foram avaliadas as cultivares Albion, Aromas, Camarosa e San Andreas. A maior viabilidade da fase ninfal foi observada em 'San Andreas' (87%) e a menor em 'Camarosa' (43%). 'Albion' apresentou o maior valor de taxa líquida de reprodução (Ro= 6,39±0,03) e o menor tempo necessário para a população duplicar (TD=5,61±0,01). Também apresentou o maior valor para a inata capacidade de aumentar em número (rm=0,12). 'Camarosa' e 'Aromas' apresentaram os menores valores de taxa líquida de reprodução (Ro= 2,65±0,17 e Ro= 2,70±0,11, respectivamente) e os maiores valores de tempo necessário para a população duplicar (TD=10,89±0,72 e TD=10,34±0,43, respectivamente). Em 'San Andreas' foram observados os valores mais baixos de risco de morte (100qx), sendo iguais a zero durante quase todo o período ninfal (0,5 a 9,5 dias) enquanto em 'Camarosa' foram observados os valores mais altos de risco de morte durante o m esmo período . Em 'San Andreas' foi observada a maior longevidade dos insetos (34,5 dias) . Com relação ao comportamento alimentar, em 'San Andreas' os insetos apresentaram maior tempo de alimentação na fase floemática que em 'Camarosa'. Em 'San Andreas', todos os insetos avaliados apresentaram fase floemática, diferindo de 'Camarosa'. Em 'Camarosa' o tempo médio de duração da fase xilemática foi superior ao da fase floemática. Os resultados obtidos sugerem que mecanismos de antibiose e de antixenose podem estar envolvidos no processo de resistência de 'Camarosa' a C. fragaefolii. Com bases nessas informações, é possível planejar a implantação da lavoura de morangueiro, passando pela escolha da cultivar adequada em função da época de plantio, até o estabelecimento de um programa de manejo integrado de pragas para afídeos; considerando a cultivar com menor potencial de crescimento populacional de C. fragaefolii e sua época de menor ocorrência.Abstract: Aphids are important pests in strawberry, causing direct and indirect damage, mainly due to sap continues suction and viruses transmission. Chaetosiphon fragaefolii is the main aphid associated with strawberry. Knowledge of the population dynamics of the pest is essential to the establishment of an efficient and rational management. The use of resistant cultivars can be an important strategy for the control of viruses transmitted by aphids. Plant resistance to insects can be studied using electronic monitoring technique (EPG). Our aim was to register the population dynamics of aphids on strawberry plants, correlating their occurrence with weather conditions and natural enemy population - and to study, under laboratory conditions, the biological parameters and feeding behavior of C. fragaefolii in four strawberry cultivars. During the period from October 2012 to July 2013, fortnightly monitoring were conducted in an experimental field of strawberry in Pinhais, Paraná. The aphid species found were: Chaetosiphon fragaefolii, Aphis forbesi and Aphis gossypii, being, the first, the predominant species. Periods of higher occurrence of C. fragaefolii and A. forbesi on the field were recorded in the months of June and July 2013. To A. gossypii, population peak was in March 2013. Climatic factors affected significantly the population density of aphids, whereas C. fragaefolli and A. forbesi showed negative correlation with temperature, and A. gossypii showed a positive correlation. Natural enemies more found were coccinellids (Coleoptera), predators (Hemiptera) and parasitoids (Hymenoptera). In laboratory experiments, the cultivars Albion, Aromas, Camarosa and San Andreas were evaluated. The highest viability in the nymphal stage was observed in 'San Andreas' (87%) and the lowest in 'Camarosa' (43%) . 'Albion' showed the highest value of net reproductive rate (R0 = 6.39 ± 0.03) and lowest doubling time (TD = 5.61 ± 0.01), and also showed the highest value for the intrinsic rate of natural increase (rm = 0.12). 'Camarosa' and 'Aromas' showed the lowest values of net reproductive rate (R0 = 2.65 ± 0.17 and R0 = 2.70 ± 0.11, respectively) and the highest values of doubling time (DT = 10.89 ± 0.72 and 10.34 ± 0.43 = TD, respectively). In 'San Andreas' the lower values of risk of death (100qx) were observed, being almost null throughout the nymphal period (0.5 to 9.5 days) while in Camarosa the highest values of risk of death were observed during the same period. The highest longevity of insects was observed In 'San Andreas' (34.5 days). In rel ati on to feeding behavior, in 'San Andreas' the insects spent more time in phloematic phase feed than in 'Camarosa'. In 'San Andreas', all insects reviews showed phloem phase, differing from 'Camarosa', where 65% of the insects reached the phloem. In 'Camarosa' the average duration of xylem phase was higher than the phloem phase. The results suggest that mechanisms of antibiosis and antixenosis may be involved in resistance 'Camarosa' process C. fragaefolii. Based on such information, it's possible to plan the deployment of strawberry plant, beginning with the choice of the proper cultivar depending on the time of planting, until the establishment of an integrated pest management program for aphids - considering the cultivar with lowest potential for population growth of C. fragaefolii and its time of lowest occurrence

Sampling methods and metereological factors on pests and beneficial organisms in strawberries

We characterize the population dynamics of pests and beneficial organisms in strawberries to assess the impact of two meteorological factors (temperature and precipitation) and define the most appropriate method for monitoring insects in strawberries crop. Population dynamics were monitored weekly using the plant beat method and Möericke traps in Albion strawberries. Measurements were taken in organic strawberry farms over two growing seasons, from March 26, 2010 to August 23, 2010 (first season - 2009/2010) and from October 4, 2010 to March 21, 2011 (second season - 2009/2010) in the municipality of Pinhais, Paraná state, southern Brazil (25º25'S; 49º08'W). We collected a total of 7,971 pests and 1,987 beneficial organisms. The most abundant pests were Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) in the first growing season and Tetranychus urticae (Koch) (Acari: Tetranychidae) in the second. Beneficial organisms from Acari, Araneae, and Hymenoptera parasitoids predominated in both seasons. Temperature and precipitation were the the primary climatic factor associated with the population variation of aphids. Populations of C. fragaefolii grew when the temperature was between 16°C and 25ºC. We found that plant beat was the fastest and most suitable method for strawberry pests monitoring since it captured insects that were effectively colonizing the plants. This study contributes to a better understanding of the entomofauna associated with cultivation of organic strawberry

Acarofauna present in organic strawberry fields and associated weed species in southern Brazil

25 Pags.- 8 Tabls. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2021.The presence of weeds in the margins of strawberry crops can enhance populations of predatory mites as a measure to support conservation biological control. The aims of this study were (i) to assess the composition of the acarofauna associated with strawberries and the accompanying herbaceous plants in an organic farming system, and (ii) to evaluate the possible relationships between phytophagous and predatory mites occurring in this system. Strawberry leaves and whole plants of weeds were sampled biweekly from August 2014 to February 2015 in Lapa (Paraná, Brazil). In total, 23 weed species belonging to 10 families were identified; 3768 mite individuals (from 15 families and 4 suborders) were recovered, 77% on strawberries and 23% on weeds. Abundance of predatory mites on weeds was greater than on strawberry cultivars. On strawberries, the most abundant family was Tetranychidae (84%) followed by Phytoseiidae (11.6%). In total, 16 predatory mite species from the Phytoseiidae family were identified, 13 of them occurring on strawberry leaflets. Typholodromalus aripo, Neoseiulus californicus and Typhlodromips mangleae were the most abundant mite species on strawberry leaves. On weeds, most individuals were predatory mites (59%), whereas phytophagous mites represented 17.2%. The most abundant family was Phytoseiidae (36.4%). On weeds, the phytoseiid mite T. aripo was the most abundant species, representing 34.7%. Besides being found on strawberry leaflets, T. aripo was associated with 15 weed species. Among the weeds, Bidens pilosa showed the highest values of the Shannon index (1.97), Margalef index (3.04), and Pielou’s evenness index (0.95). This study emphasizes the importance of surrounding weeds as a shelter for beneficial mitefauna in strawberry fields, likely contributing to enhance conservation biological control.No funding was received for conducting this study.Peer reviewe