Expansion of pea cropping increases the risk of pea moth (Cydia nigricana; Lep., Tortricidae) infestation

Abstract:  The pea moth ( Cydia nigricana ) is a host-specific pest of pea ( Pisum sativum ). In Finland, the combine-harvested field pea is grown on an area totalling 5000 ha. However, the area under pea cropping may increase substantially if pea replaces soya bean as a protein source for animal feed, which may result in pest and disease problems. In this study, the risk of pea moth infestation is evaluated by modelling field survey data. The observations were made in 2002 and 2003 at 93 and 90 pea fields, respectively, in south-western Finland. The choice of the experimental fields was based on pea cropping data from 1997 to 2001 and included regions of both intensive and less intensive pea cultivation. The occurrence of pea moth adults in the fields was assessed with pheromone traps, and the percentage of damaged pods and pea seeds in each field was determined. The number of pea moths in pheromone traps and the percentage of damaged seeds increased linearly when the area under pea cropping during the previous year (within a 4-km distance) increased, and decreased exponentially when the distance to the nearest pea field in the previous year increased. Furthermore, the percentage of damaged pods and seeds was higher in organic than in conventional fields. Expansion of pea cropping would change the spatial distribution of pea fields, thus affecting the risk of pea moth infestation. An increase in the scale and frequency of pea cropping increases the need for plant protection.     

Effects of predation on clutch size and egg dispersion in the codling moth Laspeyresia pomonella

ABSTRACT.

• 1 The effects of predation on clutch size and egg dispersion in the codling moth Laspeyresia pomonella (L.) were experimentally studied in an orchard by recording survival of eggs glued onto different substrates.
• 2 Egg mortality due to sucking insects was readily distinguishable from that due to chewing insects.
• 3 In both the field and laboratory, females preferred to deposit eggs singly on the uppersides of leaves.
• 4 Eggs on the uppersides of leaves and on fruit survived significantly better than did those on the undersides of leaves or on twigs.
• 5 Egg losses were highest during the early part of the flight season.
• 6 The smallest (one egg) and largest (nine eggs) clutches, associated with one egg-bearing leaf per twig, both suffered the lowest rates of predation. Factors selecting against oviposition on fruits and production of large clutch sizes are presented and discussed.

     

实时荧光定量PCR快速检测四种蛀果性害虫

苹果蠹蛾、香梨优斑螟、梨小食心虫及地老虎是危害新疆香梨等产品的重要害虫,前3种也属于国际上检验检疫重要虫害。目前,国内主要依靠虫体的形态特征对其进行鉴定,缺少分子生物学检测手段,这限制了我国香梨等产品的生产和出口贸易发展。首先得到这4种害虫的16S r DNA COI基因片段,在差异序列设计特异性的引物和探针,利用实时荧光定量PCR技术建立快速分子检测试验体系,依据标准曲线分析检测体系的重复性和灵敏性。结果表明,苹果蠹蛾、香梨优斑螟、梨小食心虫及地老虎最低检出限分别在1.605×10-2、0.729×10-2、0.475×10-2和0.818×10-2 ng/μL,满足检验检疫日常检测需求。为克服实际检测过程中经常会出现某一虫的残片样本或者几种虫聚集在一起的混合样本,使用了单头、多头DNA样本及4种害虫的混合DNA样本进行检测分析,进一步验证了该方法的特异性,可靠性和可适用性。     

寄生云杉球果卷蛾的姬蜂

报道采自青海省祁连县寄生云杉球果卷蛾Laspeyresia strobilella Linnaeus的3种姬蜂,其中1新种:祁连缺沟姬蜂Lissonota qilianica Sheng,sp.nov.,中国1新纪录:欧松梢小卷蛾曲姬蜂Scambus(Scambus)buolianae(Hartig,1838),对青海汤姬蜂Townesia qinghaiensis He,1996的雌性作了首次描记.标本保存在国家林业局森林病虫害防治总站.     

The influence of temperature on the behaviour of the Mexican jumping bean

1. 1.|The jumping behaviour of the Mexican jumping bean (Laspeyresia solitans) is stereotyped and predictable and has the characteristics of behaviour which is under the control of a central programme.

2. 2.|Temperatures above and below about 25°C decrease the length of time that movements occur. The movements stop relatively abruptly and not gradually. The duration of movements is apparently controlled by an internal timer whose duration of operation is influenced by temperature.

3. 3.|The frequency of movements show instantaneous temperature compensation from about 21 to 45°C (Q₁₀ = 1.23), whereas between 15 and 21°C there is a large temperature dependence (Q₁₀ = 21.9).

Termination of the facultative diapause in the codling moth, Laspeyresia pomonella (Lepidoptera, Tortricidae)

The abiotic factors regulating the termination of the facultative diapause of the mature larva of the codling moth, Laspeyresia pomonella (L.), are described. The termination of diapause under long-day conditions (LD) is influenced by: (i) the rearing temperature of the larvae during prediapause development, (ii) the duration of the preincubation period, i.e. the time for which the diapausing larvae remain under prediapause rearing conditions, (iii) the reactivating incubation, i.e. the period for which the larvae are chilled, and (iv) the complementary incubation (LD and, except in one experiment, 26°), i.e. the period after the chilling needed for the pupation of the insects. The complementary incubation is distinctly shorter if the prediapause development of the larvae takes place at rearing temperatures below 26°, i.e. 21° or 19°. The latter conditions led to 100% pupae and pupation could be accelerated by prolonging the preincubation period. In larvae reared at 26°, the prolongation of the preincubation period raised the rate of pupation to a maximum of only 56% and also caused higher mortality. On the other hand, diapause was terminated under short-day conditions if the temperature was raised to 26° after a rearing temperature of 19° and a preincubation period of 90 days.

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Beendigung der fakultativen diapause des apfelwicklers, Laspeyresia Pomonella (Lepidoptera, Tortricidae)

Zusammenfassung Es wurde untersucht, welche abiotischen Faktoren die Beendigung der fakultativen Diapause ausgewachsener Apfelwicklerlarven (Laspeyresia pomonella) steuern. Die Beendigung der Diapause unter Langtagbedingungen (LT) wird beeinflusst durch: 1. die Zuchttemperatur der Larven während der Prädiapauseentwicklung; 2. die Dauer der Präinkubation, d.h. die Zeit, während der diapausierende Larven unter Prädiapause-Zuchtbedingungen bleiben; 3. die Reaktivierungs-inkubation, d.h. eine Periode von 70 d, während der die Larven auf 4° gekühlt werden und 4. die Komplementärinkubation (LT und, ausser in einem Experiment, 26°), d.h. die nach der Kühlung bzw. dem Wechsel in der Photoperiode benötigte Zeitdauer bis zur Verpuppung. Die Komplementärinkubation ist deutlich kürzer, wenn die Prädiapauseentwicklung der Larven bei Temperaturen unter 26° stattfindet. Bei 19° verpuppten sich 100% der Larven, wobei der Zeitpunkt der Verpuppung durch die Verlängerung der Präinkubationszeit beschleunigt wurde. Bei Larven, die bei 26° gezüchtet wurden, erreichte die Verpuppungsrate lediglich 56% bei einer relativ langen Präinkubationsdauer, wobei deren Verlängerung auch die Larvenmortalität erhöhte. Nach einer Zuchttemperatur von 19° und einer Präinkubationsdauer von 90 Tagen konnte die Diapause unter Kurztagbedingungen beendet werden, wenn die Temperatur auf 26° erhöht wurde.

     

Serological study on the transmission of a granulosis virus of the armyworm,Pseudaletia unipuncta (Lepidoptera: Noctuidae), to other lepidopterous species

The synergistic (Hawaiian) strain of a granulosis virus (GV) from the armyworm, Pseudaletia unipuncta, was transmitted to Spodoptera exigua, Autographa californica, and Trichoplusia ni. The viruses isolated from these hosts were tested by radial double-immunodiffusion (RDD) and immunoelectrophoresis (IE) for their relationship to the original virus. Untreated and heat-treated virus inclusion bodies (capsules) were compared for their antigenic properties but no differences were detected. The antiserum elicited against the whole capsule was more sharply specific for the antigenic determinants than the one elicited against the dissolved capsule proteins. The viruses obtained from S. exigua and T. ni elicited precipitin lines that differed from those of the P. unipuncta GV in their electrophoretic mobility with the one-trough IE method; however, with the two-trough method, the lines fused indicating that the antigens were identical. The major precipitin line indicating identity of the viruses wasthat produced by the synergistic factor (SF) purified from the capsule proteins of the synergistic GV strain. The presence of SF in the GV produced in alternate hosts indicated that its production was virus directed. The SF was not detected in the GVs of Laspeyresia pomonella and Pieris rapae and in the nonsynergistic Oregonian GV of P. unipuncta. A field-collected GV from S. exigua exhibited a different precipitin pattern from that of the synergistic GV, but one of the precipitin lines shared partial relationship to the SF.     

Characterization of the respiratory activity of mitochondria isolated from an insect cell line CP-1268Laspeyresia pomonella

Summary Mitochondria have been isolated from the codling mothLaspeyresia pomonella, CP-1268 cell line. The mitochondrial fraction was isolated from pooled 4 d, exponential growth phase, cultures. The mitochondria were determined to be intact based on the demonstration of respiratory control, the effects of 2,4 dinitrophenol and oligomycin on respiration, the inability to oxidize NADH, and the inability of cytochromec to enhance respiration. The isolated mitochondria were able to oxidize succinate, pyruvate, malate, α-ketoglutarate, and α-glycerophosphate efficiently. Of the substrates tested, the CP-1268 mitochondria oxidized succinate most efficiently. The respiratory control ratios ranged from a high of 4.6 for pyruvate to a low of 1.7 with α-glycerophosphate. These findings confirm that the mitochondria were tightly coupled. The data also confirm the presence of three sites of oxidative phosphorylation because NAD-linked substrates had ADP-to-O ratios approaching 3 and flavoprotein linked substrates had values approaching 2.