Oryctes rhinoceros populations and behavior influenced by a baculovirus

Oryctes rhinoceros adults stopped feeding and flew less frequently, and the males mated less often after they became infected with the baculovirus of Oryctes. Monitoring the larval and adult population in Western Samoa over several years gave evidence that the incidence of the virus is dependent on the density of the O. rhinoceros population. Male beetles were more frequently infected than female bettles. Adding more virus-infected beetles to the O. rhinoceros populations of Nukunonu Atoll, where the virus had become established 5 years earlier, reduced the population significantly. The data indicated that the reduction was caused mainly by a decrease in the number of eggs deposited.     

Evaluation of infestation percentage of cotton fields to the spiny bollworm,Earias insulana Boisduval (Lep.: Noctuidae), and its relationship with pheromone traps

Spiny bollworm, Earias insulana Boisduval (Lepidoptera: Noctuidae), is one of the most important pest of malvaceous plants throughout the world, except America. In recent years, this insect has been serious pest for cotton fields in southern regions of Iran, especially Darab region of Fars province. In order to evaluate the performance of sex pheromone in reduction of infestation percentage of the spiny bollworm by mass trapping method, an experiment was carried out during year of 2012 in Darab region in Randomised Completely Block Design with six treatments and four replications. The treatments were: application of the four sex pheromone trap densities at the rates of 16, 20, 24 and 30?traps/h, application of Larvin chemical insecticide at the rate of 1?L/h and control. Percentages of infected bolls and flowers to E. insulana were weekly determined. The application of Larvin insecticide performed as the pest population reached to economic threshold level. Analysis variance of results showed that there are significant differences between time, trap number and time?×?trap interaction on infestation percentage per hectare. During sampling time, the highest infestation percentage was in control treatment and the lowest one was observed in 30 and 24?traps/h treatments. The peak of infestation percentage was seen in 18th of November. The best efficiency among treatments was observed in pheromone trap. In conclusion, using sex pheromone trap in comparison to application of insecticides can efficiently reduce infestation level of cotton fields.     

Five years of mass trapping of Ephestia kuehniella Zeller: a component of IPM in a flour mill

Results obtained by mass trapping using the synthetic pheromone (Z,E)‐9,12‐tetradecadienyl acetate (TDA) are reported. The trapping was carried out over a period of 5 years to control infestation by Mediterranean flour moth, Ephestia kuehniella Zeller, and protect a flour mill. From March 2004 till November 2008, 42 funnel traps, each baited with 2 mg of TDA, were placed in the mill. Eight additional traps were located at the exterior of the facility, especially in the wheat silo area and near the loading equipment. Over 5 years, the pheromone traps attracted a total of 54 170 male Mediterranean flour moths. The constant presence of the traps caused a marked decrease in the E. kuehniella population from 2004 to 2008. The results of the surveys show that the population density of the moth can be notably reduced and then maintained at a low level in flour mills by means of mass trapping techniques accompanied by localized insecticide treatments and careful cleaning of the various departments and of the interior of all equipment. As it is not possible at present to establish the economic injury level of insect infestation in flour mills, there is a need for investigations into how the effectiveness of IPM programs can be evaluated in more detail.     

Studies on Rhabdionvirus oryctes: III. Incidence in the Oryctes rhinoceros population of Western Samoa

The viral pathogen Rhabdionvirus oryctes [ROV] was found to be widespread in the population of Oryctes rhinoceros in Western Samoa. About 3% of the larvae and 35% of the adults were infected with ROV. Larval breeding sites more frequently contained ROV-infected insects if the sites were occupied by two broods instead of one and if there was a high density of breeding in the area. Females infected with ROV visited the breeding sites less frequently for egg-laying than healthy females. The male adults, as they increased in age, were found to be more frequently infected with ROV, but the young female adults were more frequently infected than very young or old females. The ROV-infections in adults apparently play a more important role in suppressing the O. rhinoceros population than those of larvae.     

Transmission of a baculovirus in populations of Oryctes rhinoceros

The transmission of the baculovirus of Oryctes rhinoceros, previously called Rhabdionvirus oryctes, was studied. O. rhinoceros adults became infected with the virus when kept in a mixture of sawdust and ground-up virus-killed larvae or together with other virus-infected adults. In the field, mated females were more frequently infected than unmated females. Adults developing from larvae that had survived exposure to various dosages of the virus were not infected. No virus infections occurred in larvae hatching from eggs surface-contaminated with the virus. Larvae hatching from eggs laid by virus-infected females very rarely were infected.In the O. rhinoceros population the virus is transmitted most frequently during mating, possibly when the uninfected partner contacts virus material excreted by the infected partner. The virus can be transmitted in a similar way when infected and healthy beetles feed together in palm trees. Beetles visiting larval breeding sites containing freshly virus-killed larvae can become infected. Virus-infected beetles can pass the infection to healthy larvae when visiting a breeding site.     

Studies on Rhabdionvirus oryctes: II. Effect on adults of Oryctes rhinoceros

Rhabdionvirus oryctes multiplies in adults of Oryctes rhinoceros. Adults and larvae of O. rhinoceros showed no significant difference in their susceptibility to the virus when it was inoculated into the hemocoel. Adults, collected from the natural population in Western Samoa, were found to be frequently infected with Rhabdionvirus. In the laboratory the infected adults had a shorter life-span and laid fewer eggs than the noninfected ones. Infected adults excreted virus material into the surrounding medium. This suggests a possible means of transmission of the virus in the field.     

Pheromone mass trapping of bagworm moths,Metisa plana Walker (Lepidoptera: Psychidae), for its control in mature oil palms in Perak,Malaysia

The bagworm, Metisa plana Walker (Lepidoptera: Psychidae), is an important pest of oil palms in Malaysia. A serious infestation cause yield declines of 30–40% over 2 years after attack. Successful mass trapping depends on efficient removal of adults, which reduces the chances of mating, eventually causing a decline in the population. This study was conducted in three smallholder blocks where palm age varied from 6 to 16 years. Sticky vane traps were baited with four receptive females of M. plana and placed in three transects within each trapping plot. The percentage of female bags with eggs (i.e., those pupal bags housing the female with eggs that hatched) determined the effects of trapping on mating and reproduction success. Palm yield was compared between the trapping and control plots. The number of live larvae and the percentage of bags with eggs in the trapping plots were always relatively lower (9.1–28.2%) compared to the control plots (28.6–48.6%). Trapping plots had relatively higher bunch weight (7.8–14.3 kg) compared to the control plots (4.5–9.2 kg). The bunch weight in the trapping plots increased 22% after trapping compared to 15% in the control plot. Damage ratings on the fronds declined between 35–45% in the trapping blocks. Damage ratings declined between 20% and 27% in most control plots but increased 17% in one of the blocks with an increased bagworm population. There, mass trapping reduces the chances of bagworm mating and oviposition, which leads to lower populations and, therefore, lower frond damage and higher yields.     

Spatial patterns and infestation processes in the horse chestnut leafminer Cameraria ohridella: a tale of two cities

Spatial patterns of the horse chestnut leafminer Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) population density was analysed in the cities of Bern and Brussels in order to explore its spatial population dynamics. The surveys were carried out in Bern in 1998 and 2000 and in Brussels in 2001 to assess population density in relation to local characteristics. In Brussels, population density was also measured using pheromone traps distributed over the city and collected twice per moth generation. A quantitative relationship was found between local population density (measured by pheromone traps and survey observations) and the amount of leaves left on the ground the previous fall. Several other factors were related to observed infestation levels: the occurrence of the pathogen Guignardia aesculi was inversely related to infestation by C. ohridella in Bern in 1998 and 2000, the number of horse chestnut trees within 800 m distance was positively related to infestation level in Bern in 2000, and the proportion of green areas within 100 m and the number of other horse chestnut trees within 2000 m were positively related to infestation levels in the 2001 Brussels survey. The pattern of infestation levels as a function of distance to potential population reservoirs suggested that C. ohridella re‐invades areas where overwintering leaves have been cleaned from refuge areas such as parks or urban forests. Our results indicate that the removal of leaves is a feasible first aid control measure to reduce moth population densities. However, leaf removal may not reduce moth densities when done improperly. In places where proper leaf removal is not feasible, other control measures are needed.     

Spatial and temporal dynamics of potato tuberworm (Lepidoptera: Gelechiidae) infestation in field-stored potatoes

The potato tuberworm, Phthorimaea operculella (Zeller), is a major pest of potatoes in fields and traditional storage. A common method of nonrefrigerated storage is to pile potatoes in straw-covered heaps in the field. Tubers may be stored up to 3-4 mo in this manner, until the next harvest. We studied the dynamics of potato tuber moth infestation associated with such field storage in a 12-wk experiment in Israel. We set up six potato heaps, and sampled them for potato tuber moth at different locations at weekly intervals. Potato tuber moth infestation was significantly higher at the perimeter of the heaps than at their center, but it did not differ between bottom, mid-height, and top of the heaps. The proportion of potato tuber moth-infested potato tubers increased from 10 to 65% over the course of the experiment, and the mean number of potato tuber moth larvae per tuber increased from 0.25 to 2.50. Potato tuberworm populations increased sharply after 3, 6, and 9 wk of study, possibly corresponding to successive generations that developed within the heaps. This interpretation is supported by calculations of potato tuberworm generation length based on temperature data. Catches in pheromone traps that were placed near the heaps were not correlated (spatially and temporally) with potato tuberworm densities within heaps, hinting that migration among heaps did not considerably affect within-heap population dynamics. Potato tuberworm levels were not correlated with ambient temperatures, perhaps because of the warm, humid, and constant microclimate within the heaps. We discuss the significance of our findings for control efforts of the potato tuberworm.     

Efficacy of pheromonal control of peachtree borer (Synanthedon exitiosa (Say)) in small‐scale orchards

The efficacy of pheromone‐based mating disruption for control of the peachtree borer Synanthedon exitiosa (Say) in small‐scale peach orchards (<0.1 ha) was evaluated in a total of six blocks at two locations in New Mexico, USA, from 2010 to 2015. In treated orchards, commercial pheromone dispensers were deployed at rates of approximately 500 or 600 per ha. Pheromone‐based monitoring traps were installed in each block (treated and untreated), and catches of male moths were recorded throughout each growing season to assess the effectiveness of pheromone treatments and to determine the pest's seasonal flight activity. Levels of larval trunk infestation were assessed twice yearly by inspecting all trees at and below soil level. Infestation levels in an unreplicated block of mature peaches at one site (Los Lunas) declined from 57.5% to 8.4% while under pheromone treatment (2010–2011). Pheromone treatments in this block were discontinued in 2012, and infestation levels subsequently increased to 16.9% by spring 2015. In a replicated study in four other peach blocks at the same site, annual application of pheromones from 2012 to 2014 resulted in a significant difference in larval infestations in treated blocks compared to untreated blocks. In addition, when a single block of infested peaches at a second site (Alcalde) was treated with pheromone dispensers for three consecutive years, trunk infestation levels declined significantly, but were not completely eliminated. These results indicate that mating disruption can help protect even very small orchards from damage by S. exitiosa. However, the technique is likely to be more effective where such orchards are relatively isolated and/or where the surrounding pest pressure is moderate or low.     

Subdomain II of α-Isopropylmalate Synthase Is Essential for Activity: INFERRING A MECHANISM OF FEEDBACK INHIBITION*

The committed step of leucine biosynthesis, converting acetyl-CoA and α-ketoisovalerate into α-isopropylmalate, is catalyzed by α-isopropylmalate synthase (IPMS), an allosteric enzyme subjected to feedback inhibition by the end product l-leucine. We characterized the short form IPMS from Leptospira biflexa (LbIPMS2), which exhibits a catalytic activity comparable with that of the long form IPMS (LbIPMS1) and has a similar N-terminal domain followed by subdomain I and subdomain II but lacks the whole C-terminal regulatory domain. We found that partial deletion of the regulatory domain of LbIPMS1 resulted in a loss of about 50% of the catalytic activity; however, when the regulatory domain was deleted up to Arg-385, producing a protein that is almost equivalent to the intact LbIPMS2, about 90% of the activity was maintained. Moreover, in LbIPMS2 or LbIPMS1, further deletion of several residues from the C terminus of subdomain II significantly impaired or completely abolished the catalytic activity, respectively. These results define a complete and independently functional catalytic module of IPMS consisting of both the N-terminal domain and the two subdomains. Structural comparison of LbIPMS2 and the Mycobacterium tuberculosis IPMS revealed two different conformations of subdomain II that likely represent two substrate-binding states related to cooperative catalysis. The biochemical and structural analyses together with the previously published hydrogen-deuterium exchange data led us to propose a conformation transition mechanism for feedback inhibition mediated by subdomains I and II that might associated with alteration of the binding affinity toward acetyl-CoA.     

Optimal pheromone trap density for mass trapping cacao mirids

Sahlbergella singularis Haglund and Distantiella theobroma (Distant) (Heteroptera: Miridae) are the key insect pests of cacao in Ghana and elsewhere in West Africa. Since 1954, spraying with synthetic insecticides has been the principal means of controlling these pests. In West Africa, environmental concerns, economic stimuli, and unreliable access to insecticides have stimulated interest in ecologically more benign mirid control strategies as an alternative to a total reliance on insecticides. Males of both mirid species, and those of the less damaging Bryocoropsis laticollis Schumacher, respond to the same synthetic sex pheromone blend, so pheromone‐based strategies may provide control as well as monitoring opportunities. Pheromone traps were deployed for 3 months at nine densities between two and 30 traps per 0.1 ha plot (20–300 traps ha^?1) plus an untreated control treatment in a replicated large‐scale field experiment on mature mixed Upper Amazon hybrid cacao in Ghana, in order to determine the optimal dispenser density for mass trapping, lure‐and‐kill, and/or lure‐and‐infect. At the end of the trapping period, mirid populations in the various treatments were assessed by insecticide knockdown on 400 trees and by searches to hand height on 1 200 trees, together with an assessment of mirid damage. In total 781 S. singularis and 235 D. theobroma were captured in the pheromone traps. The optimal dispenser density for S. singularis was 150 traps ha^?1. Over 300 traps ha^?1 was probably optimal for D. theobroma as a smaller proportion of the population was captured, and numbers caught per trap displayed no decline with increasing trap density. From insecticide knockdowns, mirid population density was estimated at 220–230 ha^?1, 63% of which were D. theobroma. Too few pods and orthotropic shoots were damaged by mirids to establish the efficacy of pheromone trapping for mirid control.     

Efficacy of the pheromone (3Z)‐lactone and the host kairomone (3Z)‐hexenol at detecting early infestation of the emerald ash borer,Agrilus planipennis

The invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a major pest of ash trees, Fraxinus spp., in its introduced range in North America. Field studies were conducted to quantify the efficacy of traps baited with kairomone and pheromone lures for early detection of A. planipennis infestation. A trapping experiment demonstrated that green traps baited with the kairomone (3Z)‐hexenol detected at least one adult A. planipennis in 55.3% of plots with ‘nil to low’‐density infestations and in 100% of plots with ‘moderate to high’‐density A. planipennis infestations. Mean trap captures increased significantly with increasing infestation density. In terms of the optimal number of traps per plot, when one (3Z)‐hexenol‐baited trap was placed per plot, the trap detected populations in 62% of the plots with ‘low to moderate’‐density infestations through branch sampling. Detectability was increased to 82% when two traps were placed per plot. Finally, addition of female‐produced (3Z)‐lactone pheromone to traps significantly increased detection rates at both the trap and plot level, as compared with traps baited with the host volatile, (3Z)‐hexenol, alone (88 vs. 60%, respectively). Our results are the first to demonstrate the efficacy of baited green sticky traps for detecting low‐density A. planipennis infestations, particularly when the (3Z)‐lactone pheromone is used. This combination is therefore recommended for development of early‐detection protocols against A. planipennis.     

The epizootiology of two pathogens of the coconut palm rhinoceros beetle

Two diseases of Oryctes rhinoceros caused by Metarrhizium anisopliae and a virus were introduced from Western Samoa into Tongatapu, Kingdom of Tonga, in 1969 and 1970, respectively. The fungus remained at a low incidence and did not significantly affect the beetle population. The virus disease developed to epizootic levels within 5 months and spread across the island in 15 months. The beetle population was monitored through palm damage surveys, which confirmed that the population was considerably reduced by the disease.The greater impact of the virus was attributed to its much higher power of dispersal through infected beetles.The experiment supports the view that the reduction in beetle numbers recorded previously in Western Samoa was caused by a virus epizootic.     

Bionomics of Prays citri (Lepidoptera: Yponomeutidae) and their use in a model of control by male mass trapping*

Abstract. 1. The paper describes the population dynamics of Prays citri (Milliere), relevant to the control of this pest by synthetic pheromone, as well as infestation of lemon trees in various areas and seasons. 2. The responses of males to natural and synthetic sex pheromones are compared, and ratios for the degree of attraction of traps compared with the degree of attraction of competing wild females are calculated. 3. The ratios obtained with various population densities over two seasons of the pest's activity are presented. 4. The data are used in a model simulating control of Prays citri by male mass trapping.     

二疣犀甲对油棕、椰子的风险性分析及防控策略

二疣犀甲是危害椰子、油棕等木本油料作物的重要害虫,本文从形态学、生物学、分布及危害等不同方面对该虫进行了阐述,并对其风险性进行了定性定量评价,结果表明:二疣犀甲的R值为2.0,属于高风险有害生物。同时从生物防治、物理防治、化学防治、农事操作及检验检疫技术的应用等方面制定了二疣犀甲的综合防控策略,为该虫的危害评价和防护技术的制定提供了参考。     

Management of diamondback moth,Plutella xylostella (Lepidoptera: Plutellidae) by mating disruption

Abstract Field trials were conducted in China in 2008 and 2009 to evaluate the efficacy of mating disruption (MD) on diamondback moth, Plutella xylostella, in cabbage, Brassica oleracea var. capitata. Effectiveness was positively correlated with the MD dispenser density in the field. A density of 167 MD dispensers per ha produced an average population decrease of about 50% compared to the conventional‐practice field. Significant fewer males were captured in pheromone‐treated and conventional‐practice fields than in the blank control field, but the difference was not significant between the pheromone‐treated and conventional‐practice fields. In addition, fewer eggs and larvae were observed in pheromone‐treated fields. Our results suggest mating disruption coupled with minimal insecticidal supplements is a promising solution for resistance management and control of diamondback moth infestation.     

Mass‐trapping trials for the control of pine processionary moth in a pine woodland recreational area

The pine processionary moth, Thaumetopoea pityocampa, causes serious defoliation to Cedrus, Pinus and Pseudotsuga trees, as well as health problems in humans, pets and farm animals due to their urticating hairs. Environmentally friendly strategies for the management of T. pityocampa include: removal of egg batches, removal of nests, trapping of migrant larvae, spraying microbial or Insect Growth Regulator (IGR) insecticides and biocontrol, as well as pheromone‐based adult trapping and mating‐disruption. In the present paper, results on innovative technology for the control of T. pityocampa infestation using pheromone mass‐trapping are reported. Two 1‐ha plots were identified in the study area (central‐south Italy), a pine woodland recreational site growing Pinus halepensis. In the experimental plot (MT‐plot), 10 G‐traps (funnel trap type) baited with (Z)‐13‐hexadecen‐11‐ynyl acetate sex pheromone component were placed for mass‐trapping of adults; the other plot was used as a control‐plot (C‐plot). The T. pityocampa population was monitored using the two central traps in the MT‐plot and two traps positioned in the C‐plot. In addition, the winter nests made by T. pityocampa larvae overwintering on pine trees were counted. After 2 years of mass‐trapping, the number of adults trapped by the monitoring pheromone traps decreased in the MT‐plot, but not in the C‐plot, whereas the number of nests decreased in both plots. Statistical results highlighted significant differences in trap catches between the two plots but not between years. In the case of nests, differences among plots were not significant before the mass‐trapping, but significant after 1‐year treatment. According to our results, the mass‐trapping technique is able to reduce T. pityocampa infestations. This pheromone method can be applied in combination with other control systems in the context of integrated pest management in recreational areas.     

A sex pheromone‐baited trapping system for management of sweetpotato weevil,Cylas formicarius (Coleoptera: Brentidae)

A potent male attractant of sweetpotato weevil helps in monitoring and control of sweetpotato weevil in many production areas around the world. At present, it has not been used in Malaysia. Cost of the components of a trapping system is a major constraint in the adoption of male lure‐baited trapping by growers in Malaysia. Seven field trapping experiments were conducted from February 2013 to November 2015 as part of an effort to develop a simple, easy to construct, cost‐effective and efficient sex pheromone‐baited trap acceptable for use by farmers in Malaysia for monitoring and control of sweetpotato weevil (Cylas formicarius Fabricius). Overall, sweetpotato weevil trap catch was significantly affected by the number of windows in the trap, the killing agent used in the trap and the position of the trap relative to sweetpotato foliage, while trap size and trap colour did not significantly affect trap catch. Trap catch was best in plastic pole traps made from polyethylene terephthalate, with four window opening to facilitate weevil entry, with detergent solution as a killing agent and with the trap positioned from 0 to 40 cm above the crop canopy level. In a comparison study with commercial trap designs, sex pheromone‐baited plastic pole traps caught 60%–78% more weevils than were caught in sex pheromone‐baited delta traps, wing traps or unitraps. Optimization of trap characteristics is important for improving the performance of pheromone‐baited traps for use in population monitoring or mass‐trapping efforts to minimize crop damage by sweetpotato weevil infestation.     

Metarhizium species in soil from Brazilian biomes: a study of diversity,distribution, and association with natural and agricultural environments

Metarhizium is a diverse genus of fungi adapted for different ecologies, including soil saprotrophs, entomopathogens, and endophytes. We characterized the genetic diversity and distribution of Metarhizium species in soils found in native and agricultural landscapes within Brazilian biomes (Amazon, Cerrado, Atlantic Forest, Caatinga, and Pampa). Current species limits were determined with 5′-TEF, and the genetic diversity discerned using MzIGS3 sequences. Metarhizium robertsii, Metarhizium anisopliae, Metarhizium pingshaense, and three other lineages that lie beyond currently recognized species were found. Only soils from the Amazon contained all the species. The diversity of Metarhizium species associated with native vegetation was greater than that identified in annual and perennial crops. M. robertsii was the most abundant species (65%), followed by Metarhizium sp. indet. 1, which exhibited the highest haplotype and nucleotide diversities. Metarhizium sp. indet. 3 was found predominantly in the Caatinga biome. This information increases the knowledge about diversity and belowground species composition of Metarhizium in Brazil.