Development of natural waxes dispensers for pheromones and use in mating disruption of the ambrosia beetle <Emphasis Type="Italic">Megaplatypus mutatus</Emphasis> in poplar (<Emphasis Type="Italic">Populus</Emphasis> spp) plantations

Megaplatypus mutatus (= Platypus mutatus) (Chapuis) is an ambrosia beetle native to South America that attacks live trees, mining deeply into the xylem through large tunnels. This activity weakens the structural integrity of the tree, causing severe stem-breakage and mortality. Attacks are initiated by pioneer males that select a host tree and build short nuptial galleries, to which they attract females using a sexual pheromone. Previously, we showed the potential for the strategy of pheromone-mediated mating disruption of M. mutatus in commercial poplar and hazelnut plantations in South America and Europe using polyethylene reservoir dispensers for pheromones. In the present work we replaced the polymeric reservoir dispensers by monolithic dispensers made by dispersion of the pheromone in natural waxes and the addition of kaolin and we found that: prior to pheromone deployment, the mean number of galleries per tree did not differ significantly between the control and treated plots and the same was observed after the mating disruption treatment for the control plot but not for treated plots, where the mean number of galleries were reduced. These findings confirm that mating disruption is a viable tool for management of M. mutatus in poplar plantations. Using natural wax dispensers has obvious advantages from an environmental point of view.     

Evaluation of aerosol devices for simultaneous disruption of sex pheromone communication in <Emphasis Type="Italic">Cydia pomonella</Emphasis> and <Emphasis Type="Italic">Grapholita molesta</Emphasis> (Lepidoptera: Tortricidae)

A two-year study was conducted evaluating Puffer^® aerosol dispensers (Suterra LLC, Bend, OR, USA) for mating disruption of codling moth, Cydia pomonella (L.), and the oriental fruit moth, Grapholita molesta (Busck). The Puffer^® dispenser consists of a pressurized metal canister loaded with pheromone active ingredients dissolved in solvent and housed within a circuit-controlled, plastic dispensing cabinet programmed to release an aerosol spray of pheromone at regular intervals. Puffers^® were deployed at the label-recommended rate of 2.5 ha^?1 and released ca. 5–10 mg of pheromone (depending on treatment) per 15 min during a 12-h cycle beginning each day at 15:00 h for the duration of the season. In 2005, commercially-managed apple plots (3.2–4.9 ha) were treated with Puffers^® releasing both species’ pheromone simultaneously (dual-species) or with twice the number of adjacently-deployed Puffers^® (4–6 m apart) releasing each individual species’ pheromones (single-species), while maintaining comparable overall release rates of pheromone between these two treatments. Plots 100 m away and not treated with pheromone served as the control. Disruption of male C. pomonella and G. molesta orientation to pheromone-baited traps was 46–75 and 91–98%, respectively, in Puffer^®-treated plots compared with untreated controls. There was no statistical difference in moth disruption between plots treated with dual-species and single-species Puffers^®. Fruit injury was not statistically different between Puffer^®-treated plots and control plots not receiving pheromone. In 2006, disruption of male moth orientation to traps was 24–26 and 84–97% in Puffer^®-treated plots (2.9–5.7 ha) for C. pomonella and G. molesta, respectively, compared with untreated controls. During this season, fruit injury was lower in pheromone-treated plots compared with untreated controls at mid-season, but not at pre-harvest. Combining the pheromone of both species into single Puffer^® units did not decrease efficacy of disruption compared with deploying twice as many Puffers^® releasing a similar amount of each individual species’ pheromone suggesting that multi-species disruption using Puffers^® is a viable option. However, we conclude that the efficacy of disruption attained with low-densities (2.5 ha^?1) of Puffers^® at the moth densities recorded in this study is insufficient for effective control of C. pomonella without input of companion insecticides.     

4种引诱剂林间诱捕松墨天牛效果比较

[目的]明确APF-Ⅰ型诱剂样品(A)和F型诱剂样品(C)对松墨天牛的诱捕效果。[方法]以生产上使用的APF-Ⅰ持久增强型诱剂(B)和F1型诱剂(D)为对照,在林间进行了诱杀松墨天牛成虫试验。[结果]表明:诱剂A的平均诱虫量最高,分别为诱剂B、诱剂C和诱剂D的1.17倍、1.41倍和1.58倍,且显著高于诱剂C和诱剂D。在持效试验中,诱剂A平均诱虫量也高于其他3种诱剂。在161 d诱捕期内4种诱剂诱到的松墨天牛雌虫是雄虫的1.65 1.93倍,平均1.76倍。诱剂C也优于同类产品的诱剂D。[结论]诱剂A释放信息素均匀稳定,诱虫活性和持效作用强,最适合用于林间松墨天牛的测报及诱杀防治,因此建议在松材线虫病防治工作中优先选用。     

Testing mating disruption of the horse chestnut leafminer <Emphasis Type="Italic">Cameraria ohridella</Emphasis> (Lepidoptera: Gracillariidae) in field tents

Since the beginning of the invasion of the horse chestnut leafminer, Cameraria ohridella Deschka and Dimic 1986 (Lepidoptera: Gracillariidae), into Europe over 20 years ago the damage to white flowering horse chestnut trees, Aesculus hippocastanum L (Sapindales: Hippocastanaceae) has remained extensive. This study evaluates the possible use of pheromone mating disruption as a control option against the horse chestnut leafminer. The heterogeneous distribution of ornamental trees in parks and gardens requires a different approach to evaluate pest control than in homogeneous crop fields, orchards or plantations where mating disruption is usually applied. For this reason we set up field experiments with host trees of the same age and size in field tents with a defined number of leafminers in two different densities. In the first experiment the effective quantity of newly developed C. ohridella pheromone dispensers was tested by recapturing males using traps baited with virgin females. Ninety-five percent less males were captured if three or more dispensers were positioned at a 4 m radius around the outside of an experimental tent. This set up was then used in the second experiment where male and female leafminers were released into field tents in order to assess the effect of pheromone on the reduction of leaf mining damage. Surprisingly, the pheromone dispensers were found to have no effect on the number of leaf mines at either low or high leafminer densities. Mating sites of the horse chestnut leafminer, multiple matings and distribution of pheromone dispenser are discussed as possible factors influencing the outcome in this study.     

An attempt to control <Emphasis Type="Italic">Cameraria ohridella</Emphasis> using an attract-and-kill technique

This study estimates the efficacy of an attract-and-kill (A&K) technique to control the horse chestnut leaf miner, Cameraria ohridella Deschka and Dimic (Lepidoptera, Gracillariidae), an invasive insect pest of the horse chestnut, Aesculus hippocastanum L. (Hippocastanaceae). The A&K formulation was dispensed as 50 μl droplets of paste-like matrix, containing C. ohridella sex pheromone, (8E,10Z)-tetradeca-8,10-dienal (85% + pure; 0.16% w/w) and a fast acting contact toxicant, pyrocides (94% pure; 6% w/w), applied directly to the bark of the trees. It was tested in 2003 at rates of 30 and 45 droplets/tree at the Ostrobramska site and at rates of 30, 60 and 90 droplets/tree at the Woloska site in Warsaw, Poland, for the first insect generation. A set of untreated plots (0 droplets/tree) was established at each site as well. The treatment efficacy was estimated using two indices: (1) moth catches in pheromone traps and (2) the number of mines per leaf. Trap catches were significantly higher in the untreated plots than in the treated plots regardless of the application rate in all sites. However, there were no significant differences in leaf damage amongst all plots on each site. At the “Lazienki Krolewskie” park the attractiveness of two types of pheromone sources were compared: traps were baited with rubber septum lures or with A&K droplets. The catches of C. ohridella in traps baited with lures were lower than captures in A&K droplet-baited traps, but the difference was not significant. Possible reasons for the low efficacy of the A&K method in management of C. ohridella and reducing leaf damage are discussed.     

Pre-exposure to sex pheromone did not affect mating behavior in the sweetpotato weevil <Emphasis Type="Italic">Cylas formicarius</Emphasis>

In sterile insect technique (SIT) programs, the released sterile males are important for their effectiveness. The use of sex pheromones to collect males is economical; however, pre-exposure to sex pheromones may affect male mating behavior, and would thus reduce the effectiveness of the SIT programs. Males exposed to sex pheromone may become attractive to other males due to pheromone adsorption on their body impregnation, prevent mating and reduce the dispersal of sterile males. We examined the effect of pre-exposure to sex pheromone on the mating behavior of male sweetpotato weevil Cylas formicarius. Pre-exposure to high-dose sex pheromone for 24 h did not affect the male mating behavior of C. formicarius, and the exposed males did not attract other males. These results suggest that male C. formicarius that were collected from a mass-rearing facility using sex pheromone can be effectively used in SIT programs.     

Mating disruption of the pink bollworm<Emphasis Type="Italic"> Pectinophora gossypiella</Emphasis> (Saund.) (Lepidoptera: Gelechiidae) using gossyplure PB-rope dispensers in cotton fields

The effects of mating disruption on population densities and percentage of damage of the pink bollworm Pectinophora gossypiella (Saunders) were investigated in a cotton field in central Greece, in 1992 and 1993. A 10-ha field was divided in two parts of 5 ha each. PB-rope dispensers were installed in mid-season in one part, whereas the other was used as a control field. Catches of pink bollworm moths in pheromone-baited traps and damage caused were recorded in both the treated and control fields. Results showed that moth catches were highly reduced in the treated field and, therefore, mid-season installation of dispensers was successful. Damage (%) was significantly less in the treated compared with the control field. Consequently, the field size of 5 ha seems to be adequate for the effective implementation of mating disruption.     

Challenges of pheromone-based mating disruption of <Emphasis Type="Italic">Cydia strobilella</Emphasis> and <Emphasis Type="Italic">Dioryctria abietella</Emphasis> in spruce seed orchards

Seed orchards function as the primary source of high-quality seeds for reforestation in many European countries, but their seed yields can be severely reduced due to seed- and cone-feeding insects. We evaluated various parameters of pheromone-based mating disruption for control of the moths Cydia strobilella and Dioryctria abietella, which are major pests in European Picea abies seed orchards. We applied different types of pheromone dispensers (rubber septa or wax droplets) at different densities and heights, and with different amounts of active components, covering whole orchards or part of an orchard. The efficacy of the treatment was evaluated by analysing male captures in pheromone-baited assessment traps, and presence of larvae in cones. A dramatic decrease (94–100%) in capture of males in traps occurred in all pheromone-treated plots compared to control plots for both moth species. In contrast, a subsequent reduction in larval numbers in cones was only achieved when wax droplets were used as the dispensing formulation at high density and at the highest pheromone dose tested, and only in half of the trials for each pest species. Electrophysiological recordings using antennae of male C. strobilella indicated elevated pheromone concentrations in a treated plot versus a control plot. Our results show that mating disruption has potential to reduce cone damage in spruce seed orchards caused by C. strobilella and D. abietella, but optimisation of the technique is required to achieve consistent and efficient population suppression of these pests.     

外源保幼激素类似物对白蜡虫泌蜡和发育的影响

[目的]探讨外源保幼激素类似物(JHA)对白蜡虫泌蜡和发育的影响。[方法]使用高、中、低浓度保幼激素类似物经喷施、涂干、注射处理白蜡虫2龄雄幼虫。[结果]表明:白蜡虫2龄雄幼虫经外源中等浓度保幼激素类似物(2.5 mg·m L-1)喷施处理可以显著提高白蜡虫2龄雄幼虫的个体泌蜡量,昆明地区增产率平均可达41.50%,峨眉地区增产率平均达25.56%;但此方法在2地区之间表现出差异性,原因可能与两地种虫来源所处的生态环境差异有关。在中、低浓度范围内,JHA对白蜡虫蛹体质量表现出促进作用,高浓度表现出抑制作用;JHA对蛹体长的抑制随着外源保幼激素浓度的增加而增强;外源保幼激素类似物还可以提高白蜡虫蛹的羽化率,羽化率达62.70%~81.62%。[结论]中浓度JHA(2.5 mg·m L-1)喷施处理2龄雄幼虫显著提高白蜡虫泌蜡量;白蜡虫蛹的体长与JHA浓度之间存在一定的负相关性;白蜡虫蛹的体质量表现出低浓度促进,高浓度抑制;喷施和涂干处理,高浓度可显著提高白蜡虫蛹的羽化率;白蜡虫蛹的羽化可能并不受其体质量和体长的影响。     

Blue stain fungi associated withIps cembrae (Coleoptera: Scolytidae) in Japanese larch in connection with their brood development

The association between blue stain fungi andIps cembrae Heer (Coleoptera: Scolytidae) was investigated in the Japanese larch,Larix leptolepis Gordon, in the Nagoya University Forest, Aichi Prefecture, central Japan.I. cembrae had one or two generation(s) in a year in this study area. Two blue stain fungi,Ophiostoma piceae andLeptographium sp., were isolated from the body surface of both male adults in mating chambers and female adults in parent galleries, suggesting that this beetle species was a vector of these fungi. Although no blue stain fungi were isolated from non-stained wood, both fungi were isolated from the mating chambers, the center and the uppermost end of the galleries throughout the season. The fact thatO. piceae was consistently isolated with high frequency from adults and from their galleries strongly suggested that this species would be the principal blue stain fungus infecting the beetle-attacked larch trees.     

Mating disruption controls the cherry tree borer, <Emphasis Type="Italic">Synanthedon hector</Emphasis> (Butler) (Lepidoptera: Sesiidae), in a steep orchard of cherry trees

Mating disruption of the cherry tree borer, Synanthedon hector (Butler), with synthetic sex attractant was conducted for 6 years to test the efficiency of the method to control the borer population on the slopes in the Cherry Tree Forest of Tama Forest Science Garden, Hachioji, Tokyo. No male adult moth has been captured in traps baited with the synthetic attractant since the commencement of the control. The incidence of attack decreased to a low level in the third year and has remained low thereafter, indicating the effectiveness of mating disruption in controlling the borer population.     

Factors affecting field performance of pheromone traps for tobacco beetle, <Emphasis Type="Italic">Lasioderma serricorne</Emphasis>, and tobacco moth, <Emphasis Type="Italic">Ephestia elutella</Emphasis>

Tobacco beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae), is one of the most serious insect pests of stored tobacco, and traps baited with the female-produced sex pheromone, serricornin, are used for monitoring the pest. In two trapping experiments carried out in tobacco warehouses in Greece, two commercially available trap and lure systems for L. serricorne were found to be equally effective in terms of the numbers of beetles trapped. In contrast to previous reports, anhydroserricornin was unattractive and lures containing serricornin and anhydroserricornin were less attractive than lures containing serricornin only. The sex pheromone of the other main insect pest of tobacco, Ephestia elutella (Hübner) (Lepidoptera: Pyralidae), could be added to the lures without affecting the attractiveness of either pheromone to their respective species. Lures remained attractive for at least 4 weeks under field conditions, and, in laboratory tests, release of pheromone could still be detected after 30 days at 27 °C. The stereoisomeric composition of the serricornin in the two commercial lures was similar with high proportions of the attractive (4S,6S,7S)-isomer. The proportion of the (4S,6S,7R)-isomer was low, and this is known to reduce the attractiveness.     

Fine-root dynamics of coffee in association with two shade trees in Costa Rica

Fine-root dynamics (diameter < 2.0 mm) were studied on-farm in associations of Coffea arabica with Eucalyptus deglupta or Terminalia ivorensis and in a pseudo-chronosequence of C. arabica-E. deglupta associations (two, three, four and five years old). Coffee plants were submitted to two fertilisation types. Cores were taken in the 0–40 cm soil profile two years after out-planting and subsequently in the following year in depth layers 0–10 and 10–20 cm, during and at the end of the rainy season, and during the dry season. Fine root density of coffee and timber shade trees was greater in the coffee fertilisation strip as compared to unfertilised areas close to the plants or in the inter-rows. Coffee fine roots were more evenly distributed in the topsoil (0–20 cm) whereas tree fine roots were mostly found in the first 10 cm. Although the two tree species had approximately the same fine root length density, lower coffee / tree fine root length density ratios in T. ivorensis suggest that this shade tree is potentially a stronger competitor with coffee than E. deglupta. Coffee and tree fine root length density for 0–10 cm measured during the rainy season increased progressively from two to five-year-aged associations and coffee fine root length density increased relatively more than E. deglupta fine root length density in the four and five-year-aged plantations suggesting that contrary to expectations, coffee fine roots were displacing tree fine roots.     

Flight patterns of the peach twig borer,Anarsia lineatella zell. (Lep., Gelechiidae) in central europe as observed using pheromone traps

Pheromone traps were used for monitoring phenology of the peach twig borer,Anarsia lineatella, in Central Bohemia. The pest has two generations a year, the first one (owerwintering) is usually more numerous than the second one. The peak of the flight of the first generation begins by day-degrees (DD) 400–450 °C and the peak of the flight of the second generation at DD 900–960 °C. DD data can be used for supervised control both in the case of timing the chemical treatment and for deciding on using pheromones for male confusion. The suitable term for chemical treatment in the given locality in Central Bohemia is DD 360°C (above the developmental threshold 10 °C). The injury to fruits and shoots of peach trees similar to that caused byA. lineatella does also the oriental fruit moth,Cydia molesta. According to very low catches in pheromone trapsC. molesta does not seem to be economically important in Central Bohemia at present.With 2 tables and 3 figures     

Seasonal pattern of nitrogen mineralization and soil moisture beneath Faidherbia albida (synAcacia albida) in central malawi

On fertile alluvial soils on the lakeshore plain of Malawi, maize (Zea mays L.) yields beneath canopies of large Faidherbia albida (synAcacia albida) trees greatly exceed those found beyound tree canopies, yet there is little difference in soil nutrients or organic matter. To investigate the possibility that soil nutrient dynamics contribute to increased maize yields, this study focused on the impact of Faidherbia albida on nitrogen mineralization and soil moisture from the time of crop planting until harvest. Both large and small trees were studied to consider whether tree effects change as trees mature.During the first month of the rainy season, a seven-fold difference in net N mineralization was recorded beneath large tree canopies compared to rates measured in open sites. The initial pulse beneath the trees was 60 g N g^–1 in the top 15 cm of soil. During the rest of the cropping cycle, N availability was 1.5 to 3 times higher beneath tree canopies than in open sites. The total production of N for the 4-month study period was 112 g N g^–1 below tree canopies compared to 42 g N g^–1 beyond the canopies. Soil moisture in the 0–15 cm soil layer was higher under the influence of the tree canopies. The canopy versus open site difference grew from 4% at the beginning of the season to 50% at the end of the cropping season.Both N mineralization and soil moisture were decreased below young trees. Hence, the impact of F. albida on these soil properties changes with tree age and size. While maize yields were not depressed beneath young F. albida, it is important to realize that the full benefits of this traditional agroforestry system may require decades to develop.     

Calling behaviour and male response towards sex pheromone of poplar moth <Emphasis Type="Italic">Condylorrhiza vestigialis</Emphasis> (Lepidoptera: Crambidae)

The calling behaviour of virgin females Condylorrhiza vestigialis Guenée, 1854 (Lepidoptera: Crambidae) and the female pheromone gland extract activity were studied under laboratory conditions. Most of the females started calling from their first scotophase period after emergence. Maximum calling occurred between the seventh and tenth hours of the scotophase period. The length of the calling increased with age until the fourth scotophase, but the onset of calling time did not differ with age. The number of calling bouts increased significantly with age, but the mean duration of each calling bout (20.8 min) did not vary with age. Extracts of pheromone glands evaluated in a Y-tube olfactometer attracted significantly more males than control, 70 and 30%, respectively. Gas chromatographic–electroantennogram detection (GC–EAD) analysis of these extracts indicated the presence of a single EAD-active peak, the putative sex pheromone of the species. This pheromone compound may be suitable for monitoring populations densities of C. vestigialis, and for detection of the onset of the seasonal flight period. An efficient pheromone is of importance also with respect to current attempts to develop new control methods for this important pest of Populus spp. in Brazil.     

Mit neuen Verfahren gegen Fruchtwickler in Kleingartenanlagen

The availability of pesticides in private gardens is limited by local law in the State of Baden-Württemberg in south-west Germany. Only 26 insecticides, fungicides and molluscicides are permitted. Hence, only pesticides such as Bacillus thuringiensis, Granulosis Virus, pyrethrum or the pheromone mating disruption method (PMDM) can be used for moth control in apple. The use of beneficials like Trichogramma sp. or Chrysoperla carnea is not limited. PMDM had not been previ-ously investigated in allotments until the experiments reported here were carried out in 1998 and 1999. In these experiments, PMDM was compared with the use of the egg parasites, Trichogramma dendrolimi and T. cacoeciae. The observations were done in 102 allotments, each of about 300 m². The gardeners are members of a special club for the allotments and they often organize the bulk acquisition of plants or fertilizers for the club. Sometimes the club obtains plant protection products when something has to be done in all allotments. The codling moth and the plum fruit moth are important pests in these allotments.In 1997, attacks of codling moth were generally low throughout the southern Germany. This was reflected in the allotments where there was less than one per cent fruit damage with PMDM or the egg parasites the following year. During 1999, the attacks were generally much higher resulting in a higher use of insecticides in commercial German orchards. In the allotments, about six to eight per cent of fruits were damaged by the codling moth in both experimental treatments.The results indicate that PMDM can be successful in allotments and is equally as effective as the use of egg-parasites. But further experiments are required.     

Growth and resource utilization of perennial pigeonpea (Cajanus cajan (L) Millsp.) at the tree-crop interface

Perennial pigeonpea (Cajanus cajan (L) Millsp.) was grown as a multipurpose tree species in strips or blocks with annual crops (sorghum, sunflower and chickpea) on a shallow Vertisol from 1987 to 1989. The interaction between the perennial pigeonpea and annual crops was measured at the tree-crop interface (TCI) by comparing the plants at the interface (I) and in the middle of the block planting (N).Perennial pigeonpea I plants had significantly more branches and bigger stems than N plants at the onset of the following rainy season. The greater number of flowers and grains of the I pigeonpea plants was partly due to a better lateral light level and partly due to a better access to water. On the other hand the negative effect on annual crops at the TCI extended to 1.5 m during the rainy season and to 2.5 m during the post-rainy season. Significant reduction in the growth of annual crops occurred at 30–40 days after sowing and was associated with the shading by the taller pigeonpea. Measurements of root profile of pigeonpea at the interface indicated that competition for moisture was the major cause for yield reduction of chickpea during the post-rainy season but an allelopathetic effect may also be involved. The results are compared with other TCI studies especially with Leucaena leucocephala in the semi-arid crops and the possible mechanisms for moisture interaction at the TCI are discussed.Submitted as ICRISAT Journal Article No. 1176 for Agroforestry Systems.     

Dendroclimatological regions of Douglas fir (<Emphasis Type="Italic">Pseudotsuga menziesii</Emphasis> Franco) in western Poland

Abstract Six Douglas fir (Pseudotsuga menziesii Franco) stands were selected in both the Sudety Mountains and the Great Poland Lowland. These two regions are distinctly different with regard to thermal and pluvial conditions. In each stand, two increment cores per tree were extracted from 20 approximately 100-year-old trees and the tree-ring widths measured. It is clear from the different growth reactions of the study trees to the climatic conditions that the Sudety Mountains and the Great Poland Lowland are two dendrochronologically separate regions. The tree-ring width chronologies form homogeneous groups for each region. The tree ring–climate models for Douglas fir in both regions indicate similarities and differences. The similarities among chronologies are attributed to winter temperature. The differences are attributed to rainfall (which changes with longitude and altitude of sites) during the vegetation season.     

Height growth of young larch (Larix kaempferi) in relation to the frequency of deer browsing damage in Hokkaido, Japan

The effect of browsing frequency by Sika deer (Cervus nippon yezoensis) on the height growth of Japanese larch (Larix kaempferi) in Hokkaido, Japan, was analyzed. Tree heights at the time of the census and at the start of the current growing season were determined for 100 trees selected randomly at each site. The tallest shoot on each tree was identified and the number of browsing occurrences on the current-year shoot was determined. Young larches browsed by deer repeatedly develop new shoots during a growing season. Larch is a browsing-tolerant species, and the average height growth of the most heavily browsed trees was >15 cm. Although resprouting partly compensated for decreased height growth caused by browsing, the annual increase in height decreased with increased browsing frequency. Thus, browsing frequency during a growing season best reflects the intensity of browsing damage to larch trees.