Pasquale Trematerra

Spatiotemporal Distribution of Insects and Mites in Horizontally Stored Wheat

Abstract Samples were taken from a flat storage facility located in central Greece, filled with ≈45 tons of hard wheat, to assess the spatiotemporal distribution of stored-product insects and mites. The wheat was stored in a 1.5-m-deep bulk from June 2001 until March 2002. The samples were taken with a partitioned grain trier during the entire storage period, at 10-d intervals. The trier samples were examined separately for the upper, medial, and lower 0.5 m of the bulk. The spatial distribution of the insect and mite species found was examined by contour analysis based on the numbers of individuals in the trier samples. Nine insect and 20 mite taxa were found during the sampling period. The most abundant insect species were Tribolium castaneum (Herbst), Cryptolestes ferrugineus (Stephens), and Rhyzopertha dominica (F.); the most abundant mite species were Lepidoglyphus destructor (Schrank), Acarus siro L., and the predator Cheyletus malaccensis Oudemans. &Tgr;he highest population densities for the majority of the insect and mite species were recorded during autumn. The majority of the individuals of the most abundant insect and mite species were found in the upper 0.5 m of the bulk, with the exception of C. malaccensis, which was equally distributed in the upper and medial 0.5 m of the bulk. The spatiotemporal distribution during the entire experimental period was notably varied according to the insect and mite species.

Spatial distribution of some beetles infesting a feed mill with spatio-temporal dynamics of Oryzaephilus surinamensis, Tribolium castaneum and Tribolium confusum

Food-bait traps were used to study spatial and temporal distribution of the coleopteran fauna of the first floor of a feed mill in Central Italy. A total of 3396 beetles were captured during the 1-year survey. Beetles were most abundant during July and August and least abundant during February and March. Tribolium confusum du Val was the most abundant and widespread, followed by Oryzaephilus surinamensis (L.), Tribolium castaneum (Herbst), Attagenus brunneus Faldermann, Sitophilus oryzae (L.), and Stegobium paniceum (L.). The spatial patterns of annual catches of these six species were depicted by contour maps. In addition, high catches of O. surinamensis, T. castaneum and T. confusum, allowed construction of contour maps for monthly trap catches. The populations of A. brunneus were located in the bagging, milling, formulation and pelleting sites, and in the area around the conveyer belt. The highest populations of O. surinamensis were in the entry zone of the unloading pit and in the area around the conveyer belt with finished products. Sitophilus oryzae were present near the entry door of the unloading pit room, around the storage bins and in the storeroom. Populations of S. paniceum were found in the unloading pit as far as the conveyer belt and in a corner of storeroom. Tribolium castaneum was limited to a localized area in the room where raw material was processed and in the entry to the unloading pit room. The highest T. confusum populations were located in the milling, formulation and pelleting sites, and near balance and storage bins. Comparison of the spatio-temporal dynamics of these pests showed a segregation of populations, in both time and space, and a strong interaction among species is suggested. On the basis of our results, the spatial and temporal distributions are significantly affected by various factors, such as food availability, processing practices and temperature conditions in different areas.

Geostatistical characterization of the spatial distribution of Grapholita molesta and Anarsia lineatella males in an agricultural landscape

Abstract:  The results obtained in spatial analysis of pheromone trap catches of oriental fruit moth, Grapholita molesta (Busck) and Peach twig borer, Anarsia lineatella (Zeller), are reported. The studies were performed in the Molise region, central Italy, during 2002 and 2003. Local distributions of oriental fruit moth and peach twig borer males were considered in a heterogeneous landscape. The aim of the study was to determine the temporal and spatial variation in distribution and abundance of the insect pests inside small plots of fruit orchards (apple, kiwi, peach, pear and plum fruits) and outside (in field crops, irrigation channels, hedgerows and a river), and to evaluate the importance of the host plants in relation to the adult distributions. Results showed that the main ‘hot spot’ for both lepidopterous pests was in a stone fruit orchard in the northern zone of the study area; other infested areas were in stone orchards and, in the case of A. lineatella, also in plum orchards. The river seems to act as a barrier rather than an ecological corridor. The observed spatio‐temporal distributions of G. molesta and A. lineatella differed and were determined mainly by the location of the most important host plants and by the tendency of males to move in the environment, i.e. inside and outside the breeding and mating sites. Adequate knowledge of these spatial processes should be considered as an essential prerequisite for integrated pest management programmes in a precision farming approach.

Ultrasound production in the courtship behaviour of Ephestia cautella (Walk.), E. kuehniella Z. and Plodia interpunctella (Hb.) (Lepidoptera : Pyralidae)

Abstract Ultrasonic emission in the mating behaviour of three species of Lepidoptera: Pyralidae, Ephestia cautella (Walk.), E. kuehniella Z. and Plodia interpunctella (Hb.), is reported. Sounds consist of quite regular sequences of ultrasonic pulses reaching a frequency of up to 80 kHz, emitted by wing-fanning males during courtship behaviour. Preliminary results on the role of the emission in pair-forming is discussed.

Spatio-temporal analysis of insect pests infesting a paddy rice storage facility

The study describes the temporal and spatial distribution of the insect fauna collected in a paddy rice storage facility over two years, with major emphasis on the most abundant pests. The experiment, using 19 food-bait traps, was carried out in the county of Massaranduba, State of Santa Catarina, Brazil, from November 1997 to October 1999. During the whole survey, Sitophilus oryzae (L.), a primary pest associated to stored cereals, was the most abundant species in the storage facility (28,542 specimens captured). Other beetles were collected in remarkable numbers, both primary pests, such as Rhyzopertha dominica (Fabricius) (3,931 specimens), and secondary pests, such as Cryptolestes ferrugineus (Stephens) (4,075 specimens) and Oryzaephilus surinamesis (L.) (1,069 specimens). In general, various species showed very variable distribution and, depending on pest and year, all parts of the facility appeared infested. Pest populations were present both in processing area and in silos, at least in one of the two years survey. Analyzing different distributions, the various zones of the rice facility appeared to have different propensity to insect infestations, with the south-eastern silos and the grain pit with the conveyor belt as the most frequently infested. Moreover, variations between the 1st and 2nd year survey showed a strong decrease of total population numbers in the 2nd year, but in different ways, depending on the species considered. Such a result was probably due to the cleaning measures accomplished inside and outside the silos and in the processing area, including application of insecticide on the structure.

Spatial associations of insects and mites in stored wheat.

ABSTRACT The spatial association pattern of insect and mite populations in a steel bin containing stored wheat, Triticum durum Desf., in central Greece, was studied using the Spatial Analysis by Distance IndicEs (SADIE). The monitoring was carried out for 7 mo by using grain trier samples and probe traps. The most abundant insect species were Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae) and Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae). For mites, the most abundant species were the phytophagous Lepidoglyphus destructor (Schrank) (Acari: Glycyphagidae) and the predator Blattisocius tarsalis (Berlese) (Mesostigmata: Ascidae). Both for P. interpunctella and C. ferrugineus, trap catches were associated with numbers of individuals in the trier samples, but the overall association index calculated among trap and sample counts was significant only in the 33% of trap-sample pairs of values. Generally, P. interpunctella had the main patch areas in the central part of the bin, with few exceptions, during the entire monitoring period. Similar trends also were noted in the case of C. ferrugineus, which was clearly aggregated in the center of the grain mass. Spatial association maps indicated a stable positive association in the central part of the bin, but in most of the other sampling zones the association was negative. However, distribution of L. destructor, based on trier samples, indicated increased presence in peripheral zones of the grain sampling area. Moreover, B. tarsalis presented the most dispersed distribution among all four species. For each species, the association between two consecutive samplings was significant in the majority of cases, indicating a stable spatial pattern. Finally, B. tarsalis was spatially associated to a higher degree with the insects found rather than with L. desctructor. Moreover, there was no association of insect and mite presence with grain temperature and moisture content. The results of the current study suggest that the coexistence of insects and mites in bulked grain follows a complex pattern, with significant interactions, especially in the case of mite predators, which are spatially associated with insect species.

Spatio-temporal distribution of Ceratitis capitata population in a heterogeneous landscape in Central Italy

The spatio‐temporal dynamics of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was investigated to evaluate the effect of the landscape elements and host plants on pest distribution, in an agricultural landscape of 500 ha located in Central Italy. Two farms (farm 1 and farm 2) are located in the experimental area, composing mixed fruit orchards and surrounded by hedgerows, small woodlots, private gardens and cereal fields. Ceratitis capitata population fluctuation was monitored, from 2006 to 2008, using traps baited with trimedlure. Geostatistical methods such as Inverse distance squared weighted were used to obtain distributional maps of adults, mainly males. Results showed that the adult Mediterranean fruit flies were primarily distributed inside farm 1, with the maximum density found in the months of September and October. Away from the principal host plants, particularly in cereal fields, the number of trapped individuals was always low or zero. In both farms, flies were caught sequentially in traps located on host plants (i.e. peach, apple, pear, oriental persimmon and prickly pear) at varying times of maturation, especially when fruits remained on the trees. Distributional maps provided evidence that allowed to identify habitats in which the fly developed early in the season (mixed peach orchards) and afterwards during the periodic flights.

Spatial Analysis of Lobesia botrana (Lepidoptera: Tortricidae) Male Population in a Mediterranean Agricultural Landscape in Central Italy

Abstract The results obtained from the spatial analysis of pheromone-baited trap catch data of Lobesia botrana (Denis and Schiffermüller) males are reported. The research was undertaken in the Abruzzo region of central Italy. In the study area, vineyards (of Vitis vinifera L.) are the predominant cultivation, surrounded by hedgerows and small woodlots, and interspersed with cereal crops and olive groves. The main purpose of the study was to investigate the spatio-temporal dynamics of L. botrana, inside and outside vineyards, and to evaluate the effect of the landscape elements on pest distribution. A trend orientation over the experimental area was observed along the direction from northwest to southeast. Correlograms fitted using a spherical model showed in all cases an aggregated distribution and an estimated range having a mean of 174 m in 2005 and 116 m in 2006. Contour maps highlighted that spatial distribution of L. botrana was not limited to vineyards, but its presence is high particularly inside olive groves. The adult distribution on the experimental area changed during the season: hot spots of flight I were positioned inside olive groves; during flights II and III, they were concentrated in vineyards. L. botrana males were also captured in uncultivated fields, but never in high densities. Our results showed that a large proportion of the adult population of L. botrana inhabits areas outside those usually targeted by pest management programs. Thus, in Mediterranean agro-ecosystems, it is highly recommended to consider the whole landscape, with particular attention to olive crops.

Advances in the use of pheromones for stored-product protection

Considerable progress has been made in the monitoring and control of stored-product pests, mainly Lepidoptera and Coleoptera, by pheromones, which are used in mass trapping, attracticide and mating disruption methods. In integrated pest management programmes of stored-product protection, the use of pheromones can lead to a reduction in chemical treatments, with economic advantages and the improvement of food-product quality. In this article, I report some promising results offering efficient detection and control of stored-product pests based on pheromones and line up a number of remaining questions to be answered to improve the reliability and competitiveness of the methods used.

Influence of intact and damaged cereal kernels on the behaviour of rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae)

The behavioural activity of Sitophilus oryzae towards intact and damaged kernels of 5 types of cereals—Triticum aestivum, T. durum, T. dicoccum, T. monococcum and T. spelta—was examined. The cereals are attractive in diAerent ways; naturally dehulled and hulled cereals release volatile substances once artificially dehulled or split. However, dehulling and splitting the kernels aAects the behaviour of S. oryzae in diAerent ways. The substances released from diAerent parts of the kernel act independently of one another. The pericarp layers may prevent these volatile substances from being released; in hulled cereals, the chaA increases the protection against their release. Once removed, volatile substances are released but only in small amounts compared to the case in which kernels are split. The release mechanism was identical for all cereals examined. Thus, in order of decreasing attraction are: the germ part, the kernel endosperm without the germ, the kernel pericarp layers, the whole kernel without the chaA, the whole kernel with the chaA, and lastly the chaA. # 1999 Elsevier Science Ltd. All rights reserved.