Tempo de eclosão e comportamento de larvas da broca-pequena-do-tomateiro, Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae)

Neoleucinodes elegantalis (Guenée) é uma das pragas mais sérias do tomate em várias regiões do Brasil. A fêmea deposita seus ovos no cálice ou nos frutos em desenvolvimento, e logo após a eclosão a larva penetra no fruto, onde permanece até a pupação. Depois que a larva entra no fruto, inseticidas e agentes de controle biológico são relativamente ineficazes. Como N. elegantalis é mais suscetível a métodos de controle quando a larva encontra-se no exterior do hospedeiro, seria vantajoso conhecer o período de tempo necessário para o desenvolvimento dos ovos e quanto tempo a larva passa na superfície do fruto. Para responder estas questões, detalhados estudos comportamentais foram conduzidos. Ovos foram coletados no campo e mantidos em câmara ambiental a 20°C, 75 ± 5% U.R., e fotoperíodo de 12L:12E. O horário de eclosão foi registrado com uma câmera de vídeo, enquanto que o comportamento da larva e o tempo requerido para que ela penetre no fruto foram determinados com observações visuais. A maioria dos ovos (93%) eclodiu dentro das primeiras duas horas da fotofase. Larvas passaram 51,1 ± 31,1 (média ± erro padrão) min na superfície do fruto. Uma vez que sítios adequados eram identificados, as larvas necessitaram de 23,8 ± 19,4 min adicionais para entrar completamente nos frutos. Oitenta e seis por cento das larvas penetram com sucesso no fruto. Destas, 42% selecionaram a porção superior, 18% selecionaram a porção média, e 40% selecionaram a porção inferior do fruto.In several regions of Brazil, Neoleucinodes elegantalis (Guenée) is one of the most serious tomato pests. The moth lays eggs on the calyx or developing fruit, and shortly after eclosion larvae penetrate into the fruit, where they remain until pupation. Once larvae have entered the fruits, insecticides and biological control agents are relatively ineffective. Because N. elegantalis is most susceptible to conventional treatments when the larvae are outside the host tissues (or fruit), it would be advantageous to know the time required for egg development and the length of time that the larvae spend on the surface of the fruit. To answer these questions detailed behavioral studies were untaken. Eggs were collected from the field and maintained in an environmental chamber at 20°C, 75 ± 5% R.H., and a 12L:12D photoperiod. The time of egg eclosion was recorded with a video camera, whereas larval behavior and time required to enter the fruit were determined by direct observations. The majority of eggs (93%) hatched within the first two hours after the beginning of photophase. Larvae spent 51.1 ± 31.1 (mean ± SEM) min on the surface of the fruits. Once a suitable site was identified, larvae required an additional 23.8 ± 19.4 min to completely enter the fruit. Eighty-six percent of the larvae were successful in penetrating the fruit. Of the larvae that bored into the fruit, 42% selected the upper portion, 18% selected the middle portion, and 40% selected the lower portion

Observations on the biology of Prionus californicus on hops in Idaho

The damage potential, seasonal flight activity and larval development of Prionus californicus were investigated over five years in Idaho hop yards. Hop plants were not susceptible to oviposition and larval establishment until after their second year. Crowns of severely infested plants were reduced to masses of frass and rotted areas. Major roots were frequently tunneled and girdled. First foliar symptoms were loss of vigor and often one or more wilted and yellowing shoots. Some affected plants died within a few months while others became less vigorous over several years. Two kinds of damage occurred: the first was from larvae that developed within root systems in established yards; the second was root damage to new plantings from larvae left in the soil when the old yard was taken out and replanted to hops. Beetle flight occurred only during July with day-to-day variation at least partially related to minimum temperatures and to precipitation. Young larvae were found almost entirely in the vascular region of roots to a soil depth of about 200 mm. Older larvae were in both living and dead roots to a soil depth of about 500 mm. Based upon measurements of 243 larvae taken from 50 hop root systems, the life cycle of the species is usually 4 years

A Critical Examination of Flight by the Sweet Potato Whitefly

In the past we have assumed that sweet potato whiteflies, Bemisia tabaci (Gennadius), were poor fliers with a limited ability to disperse. This assumption was based on the fact that sweet potato whiteflies are extremely small insects (24 -44 μg) and consequently would be subject to desiccation. We also thought small size would limit their capacity to store sufficient energy reserves to sustain flight for long periods of time. Recent experiments have indicated we were wrong on several counts. Data collected in the laboratory using a vertical flight chamber have revealed a number of interesting facts. Of importance is the fact that a portion of the population is capable of sustaining flight for more than 2.5 hours. In a wind-aided situation, this means they can be moved more than 25 miles in a 10 mph wind. Other details of flight behavior are being made clear to us. For example, we found that flight activity is influenced by host plant quality and age of the whitefly. We hope to eventually be able to predict when whiteflies are going to migrate between crops. This will allow growers to make informed decisions concerning planting dates. We are also working in the field to confirm laboratory results

Eclosion time and larval behavior of the tomato fruit borer, Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) Tempo de eclosão e comportamento de larvas da broca-pequena-do-tomateiro, Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae)

In several regions of Brazil, Neoleucinodes elegantalis (Guenée) is one of the most serious tomato pests. The moth lays eggs on the calyx or developing fruit, and shortly after eclosion larvae penetrate into the fruit, where they remain until pupation. Once larvae have entered the fruits, insecticides and biological control agents are relatively ineffective. Because N. elegantalis is most susceptible to conventional treatments when the larvae are outside the host tissues (or fruit), it would be advantageous to know the time required for egg development and the length of time that the larvae spend on the surface of the fruit. To answer these questions detailed behavioral studies were untaken. Eggs were collected from the field and maintained in an environmental chamber at 20&deg;C, 75 &plusmn; 5% R.H., and a 12L:12D photoperiod. The time of egg eclosion was recorded with a video camera, whereas larval behavior and time required to enter the fruit were determined by direct observations. The majority of eggs (93%) hatched within the first two hours after the beginning of photophase. Larvae spent 51.1 &plusmn; 31.1 (mean &plusmn; SEM) min on the surface of the fruits. Once a suitable site was identified, larvae required an additional 23.8 &plusmn; 19.4 min to completely enter the fruit. Eighty-six percent of the larvae were successful in penetrating the fruit. Of the larvae that bored into the fruit, 42% selected the upper portion, 18% selected the middle portion, and 40% selected the lower portion.<br>Neoleucinodes elegantalis (Guenée) é uma das pragas mais sérias do tomate em várias regiões do Brasil. A fêmea deposita seus ovos no cálice ou nos frutos em desenvolvimento, e logo após a eclosão a larva penetra no fruto, onde permanece até a pupação. Depois que a larva entra no fruto, inseticidas e agentes de controle biológico são relativamente ineficazes. Como N. elegantalis é mais suscetível a métodos de controle quando a larva encontra-se no exterior do hospedeiro, seria vantajoso conhecer o período de tempo necessário para o desenvolvimento dos ovos e quanto tempo a larva passa na superfície do fruto. Para responder estas questões, detalhados estudos comportamentais foram conduzidos. Ovos foram coletados no campo e mantidos em câmara ambiental a 20&deg;C, 75 &plusmn; 5% U.R., e fotoperíodo de 12L:12E. O horário de eclosão foi registrado com uma câmera de vídeo, enquanto que o comportamento da larva e o tempo requerido para que ela penetre no fruto foram determinados com observações visuais. A maioria dos ovos (93%) eclodiu dentro das primeiras duas horas da fotofase. Larvas passaram 51,1 &plusmn; 31,1 (média &plusmn; erro padrão) min na superfície do fruto. Uma vez que sítios adequados eram identificados, as larvas necessitaram de 23,8 &plusmn; 19,4 min adicionais para entrar completamente nos frutos. Oitenta e seis por cento das larvas penetram com sucesso no fruto. Destas, 42% selecionaram a porção superior, 18% selecionaram a porção média, e 40% selecionaram a porção inferior do fruto