Fecundidade e longevidade de Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) em diferentes temperaturas e cultivares comerciais de crisântemo (Dendranthema grandiflora Tzvelev)

Abstract

ABSTRACT. Fecundity and longevity of Aphis gossypii Glover, 1877 (Hemiptera, Aphididae) at different temperatures and commercial chrysanthemum cultivars (Dendranthema grandiflora Tzvelev). The aphid A. gossypii is one of the main pests in a number of crops both under field and protected conditions. The objective of the present study was to evaluate the fecundity and longevity of A. gossypii under different temperatures and commercial chrysanthemum cultivars (Yellow Snowdon, White Reagan and Dark Splendid Reagan) with different trichomes densities (11.3; 16.6 and 21.6 trichome/mm 2 of the leaf, respectively) The trials were carried out in climatic chambers, at four temperatures (15, 20, 25 and 30 ±1 °C), 70 ± 10% RH and photophase 10h. The reproductive period significantly decreased with increase of temperature in the three cultivars. In Yellow Snowdon cultivar average duration of the reproductive period was 14.3 days at 25 °C. The maximum fecundity was obtained at the temperature of 25 o C with 3,1; 2,8 and 3,6 nymphs/female/day in the Yellow Snowdon, White Reagan and Dark S. Reagan cultivars, respectively. The total fecundity was reduced by extreme temperatures (15 and 30 °C), and was obtained at 25 °C with 35,9 nymphs/female. Females maintained in Yellow Snowdon cultivar significantly showed superiority (30,7 nymphs/female) in total fecundity in relation to White Reagan (22,1 nymphs/ female) and Dark S. Reagan (22,9 nymphs/female). The Yellow Snowdon cultivar (with a lower trichome density) had a significant influence in daily and total capacity of nymphs production, showing a higher fecundity of A. gossypii females. The aphid's longevity was affected by cultivars and temperature, and this longevity decreased whit increase of temperature. The results showed that there was an interaction between the temperature and host plant on reproductive parameters of A. gossypii. KEYWORDS. Aphis gossypii; biology; reproduction; trichome. INTRODUÇÃOAphis gossypii Glover, 1877 (Hemiptera, Aphididae), apresenta ampla distribuição mundial e encontra-se associado a culturas de grande importância econômica. Constiui-se numa das principais pragas em ambientes protegidos tanto nas regiões de clima temperado como nas de clima tropicais. É uma espécie polífaga, capaz de transmitir mais de 50 viroses de plantas (BLACKMAN & EASTOP 1984). Esta espécie, assim como Myzus persicae (Sulzer, 1776) é praga primária em cultivos de crisântemo em casas-de-vegetação no Brasil (BUENO 1999).O aumento da área de produção intensiva da cultura de crisântemo, principalmente no interior de casas-de-vegetação, tem favorecido o aparecimento desses insetos em níveis populacionais capazes de provocar prejuízos econômicos à cultura (BERGMANN et al. 1996). Os pulgões são conhecidos como "estrategistas r", isto é, são muito bem adaptados para explorar temporariamente um novo habitat, através de um rápido aumento da população. RABASSE (1980)

Factors affecting colonization and abundance of Aphis gossypii glover (hemiptera: aphididae) on okra plantations

“…(CHAU et al, 2005;MEN et al, 2004;RHAINDS & MESSING, 2005;SANTOS et al, 2003;SOGLIA et al, 2002SOGLIA et al, , 2003, leaf N and K, leaf organic compounds analyzed and trichomes were apparently not important in this study. The trichomes (% non-glandular) found in okra were of low density and did not contain toxic compounds, which could present antibiotic and nonpreference effects.…”

“…Rhainds & Messing (2005) Although no significant effects (P > 0.05) of plant age, total rainfall and median temperature on aphid population were observed, in June and October, when plants were 86 and 140 days old respectively, there was a drastic decrease in the insect population, probably due to, besides natural enemies, plant senescence and/or associated with rainy season (total rainfall = March: 189 mm, April: 25 mm, May: 0 mm, June: 24 mm, July: 0 mm, August: 0 mm, September: 32 mm, October: 125 mm and November: 509 mm). High rainfall is an important mortality factor of A. gossypii in the field (MCDONALD et al, 2003;RHAINDS & MESSING, 2005) and this insect is considered to be initial pest due to changes in plant quality as the crop gets older (MEN et al, 2004;RHAINDS & MESSING, 2005;SANTOS et al, 2003;SOGLIA et al, 2002).…”

“…However, in the present study, we observed higher attack of this insect in the bottom and medium rather than in the apical part of okra plants. A plausible explanation, besides leaf areas (RHAINDS & MESSING, 2005;SECHSER et al, 2002), for the non-occurrence of attack preferentially on the apical leaves is that these leaves have more trichomes, which can make locomotion, feeding and reproduction of A. gossypii difficult (SANTOS et al, 2003;SOGLIA et al, 2002SOGLIA et al, , 2003, despite the absence of significant relationship between them.…”

“…Also, plant phenology such as leaf position on plant canopy, plant age, leaf areas, and trichomes besides natural enemies and weather can influence population of A. gossypii (CHAU et al, 2005;338 Ciênc. agrotec., Lavras, v. 31, n. 2, p. 337-343, mar./abr., 2007MEN et al, 2004RHAINDS & MESSING, 2005;SANTOS et al, 2003;SATAR et al, 2005;SECHSER et al, 2002;SOGLIA et al, 2002SOGLIA et al, , 2003. Since effects of such factors on okra plants are little known, the aim of the present investigation was to evaluate the effects of predators, parasitoids, leaf organic compounds, levels of N and K, leaf trichome density, canopy height, plant age, leaf areas, rainfall and temperature on attack intensity of A. gossypii on successive okra plantations under field conditions.…”

Biologia de Aphis gossypii Glover, 1877 (Hemiptera: Aphididae ) em abobrinha cultivar caserta (Cucurbita pepo L.) em diferentes temperaturas

“…Estudos realizados por Aldyhim & Khalil (1993), Kocourek et al (1994), Vansteenis & El-Khawass (1995), Xia et al (1999) e Soglia et al (2003) evidenciaram que há variação dos aspectos biológicos de A. gossypii em função da temperatura do ambiente em que se desenvolvem. Assim, devido à importância do pulgão A. gossypii como praga das cucurbitáceas, bem como ao conhecimento relativamente restrito sobre sua biologia em plantas de abobrinha, o presente trabalho teve como objetivo estudar alguns aspectos biológicos desse afídeo na cultivar Caserta (Cucurbita pepo L.) em diferentes temperaturas.…”