At present just about 30% of the waste plastic collected is efficiently recycled, while the rest ... more At present just about 30% of the waste plastic collected is efficiently recycled, while the rest is incinerated, disposed in landfills, or can end up in compost and be released in the environment, inducing a very negative effect on safety and health of flora and fauna. Sustainable management of hardly recyclable plastic waste generated by light weight single use packaging and agricultural films can be improved by applying biotechnological approaches, combining microorganisms, new enzymes, earthworms, and insects to work collaboratively, not only to promote the degradation of these plastics but also to obtain, by-products of the biodegradation process to be valorized as fertilizers, functional polysaccharides, etc. In order to develop a feasible process, mapping and characterization of the most diffused agri-food waste plastic were conducted isolating the main types of plastic involved. Plastic waste in agriculture is mainly constituted by polyethylene (PE) both linear low density (L...
Rhynchophorus ferrugineus (Olivier, 1790) is an invasive pest species that constitutes one of the... more Rhynchophorus ferrugineus (Olivier, 1790) is an invasive pest species that constitutes one of the most important problems around the Mediterranean region and has been responsible for the loss of over 100,000 palm trees with an estimated annual cost of EUR several hundred million since its introduction into Europe. Methodological approaches of conservation ecology, such as multidisciplinary modelling, also apply in the management of cultural landscapes concerning ornamental plants, such as palm trees of the area. In this paper, we propose a dynamic model for the control of the red palm weevil, contributing in this way to the sustainability of an existing cultural landscape. The primary data set collected is a sample from the density-time function of a two-cohort pest population. This data set suggests a bimodal analytic description. If, from this data set, we calculate a sample from the accumulated density-time function (the integral of the density-time function), it displays a doubl...
We propose a conceptual model for pollination and fertilization of tomato flowers in greenhouses ... more We propose a conceptual model for pollination and fertilization of tomato flowers in greenhouses crops by hoverflies, when the maximal number of adult pollinators maintained by the crops is less than what is needed for an economically successful pollination in greenhouses. The model consists of a two-stage process for additional feeding of hoverfly to maintain the pollinator density at the economically desired level. First, with a stochastic model, we calculate the density of flies necessary for the economically successful pollination, determined according to the economically expected yield. Second, using a deterministic optimal control model, we find a minimum cost supplementary feeding strategy. In summary, we theoretically demonstrate, at the present stage of the research without validations in case studies, that optimal supplementary feeding can maintain the economically desired hoverfly density.
Although a large number of pesticides of different compositions are regularly used in agriculture... more Although a large number of pesticides of different compositions are regularly used in agriculture, the impact of pesticides on the physiology of field crops is not well understood. Pesticides can produce negative effects on crop physiology―especially on photosynthesis―leading to a potential decrease in both the growth and the yield of crops. To investigate these potential effects in greenhouse sweet peppers, the effect of 20 insecticides and 2 fungicides (each sprayed with a wetting agent) on the photosynthesis of sweet pepper leaves was analyzed. Among these pesticides, nine caused significant reductions in photosynthetic activity. The effects were observed in distinctive ways—either as a transitory drop of the photosynthetic-rate values, which was observed at two hours after the treatment and was found to have recovered after 24 h, or as a sustained reduction of these values, which remained substantial over a number of days. The results of this study suggest that the production of...
The South American Tomato Pinworm, Tuta absoluta (Meyríck) causes important damages ín tomate cro... more The South American Tomato Pinworm, Tuta absoluta (Meyríck) causes important damages ín tomate crops in Spain; nevertheless, the damages are dífferent in open air crops, spríng - summer cycle, with constant and increasing infestations by overlap populations; respect to greenhouse crops, autumn - spring cycle, ín that the attacks take place at first and at the end of the crop cycle and that originate from discreet populations. Therefore, the control methods, according to the kind of crops, must be different; also, the varieties used in every case are different. For it, the aim of this work was to study the influence of the cultivated host plant on the efficiency and activity of biological control agents. The works were carried out in a greenhouse (1,000 m2), transplanted with plants of 5 tomate varieties, more representative of two types of crops, as mentioned befare: Razymo® Rijk Zwaam, Realeza® Ruiter Semillas, Tovi Star® Zeraim Ibérica, Tyty® Syngenta Seed and Vernal® Enza Zadem; t...
In Western Europe, including Southern Europe to Greece, four Noctuid species, belonging to the co... more In Western Europe, including Southern Europe to Greece, four Noctuid species, belonging to the corn earworm complex, are quite common: Helicoverpa armigera Huebner, Heliothis peltigera Schiffermueller, Heliothis viriplaca Hufnagel, and Heliothis nubigera Herrich Schaefer, the last in Spain and Portugal. H. armigera is the most destructive of them in Southern Europe, causing economically significant crop losses on corn, tomato, cotton, tobacco and many other host plants.A summary of the data on biology, migration and seasonal occurrence on several crops is presented for Heliothis spp. Parasitoids and predators are presented, as well as host plants. The establishment of a European Workshop on Heliothis spp. is mentioned. The concerned research centers are presented, with their main work on the pest and its host plants, and research on parasitoids, rearing techniques and release.
For the monitoring of population systems, mathematical systems theory offers an efficient method.... more For the monitoring of population systems, mathematical systems theory offers an efficient method. The concept of observability can guarantee at theoretical level the possibility of recovering the time- dependent state of a whole population system from the observation of the certain components. Once local observability near an existing equilibrium is proved, we also need a constructive method for the estimation of the state process. To this end an auxiliary system, the so-called observer system can be applied. The latter is constructed from the observed data, and asymptotically estimates the complete state process with exponential speed of convergence. The methodology used for the construction of the observer system is based in the observer design of Sundarapandian. For the illustration of this methodology, a population system modeling the biological control of the sugarcane borer (Diatraea saccharalis) by the egg parasitoid Trichogramma galloi and the larvae parasitoid Cotesia flavi...
The beet armyworm, Spodoptera exigua, is a highly polyphagous insect pest that affects various ag... more The beet armyworm, Spodoptera exigua, is a highly polyphagous insect pest that affects various agricultural crops including vegetables and ornamentals. It is a serious pest in several greenhouse crops, including pepper and watermelon. In turn, the predator Nabis pseudoferus, a member of the Nabidae family, is a strictly zoophagous species that is commercially available in Spain. Several trials were carried out on the biology and ecology of the pest and predator species in pepper crops grown in southern Spain, under both laboratory and greenhouse conditions. This work describes trials to evaluate the efficacy of the predator species for controlling different levels of pest infestation in commercial pepper greenhouses. With the resulting data, a degree-day dependent and stage-structured dynamic mathematical model for predator-prey systems was developed and validated. From the results, it can be seen that the “degree of depression” found in the prey population between the first and sec...
The classical Holling type II functional response, describing the per capita predation as a funct... more The classical Holling type II functional response, describing the per capita predation as a function of prey density, was modified by Beddington and de Angelis to include interference of predators that increases with predator density and decreases the number of killed prey. In the present paper we further generalize the Beddington-de Angelis functional response, considering that all predator activities (searching and handling prey, fight and recovery) have time duration, the probabilities of predator activities depend on the encounter probabilities, and hence on the prey and predator abundance, too. Under these conditions, the aim of the study is to introduce a functional response for fighting the predator and to analyse the corresponding dynamics, when predator-predator-prey encounters also occur. From this general approach, the Holling type functional responses can also be obtained as particular cases. In terms of the activity distribution, we give biologically interpretable suffi...
At present just about 30% of the waste plastic collected is efficiently recycled, while the rest ... more At present just about 30% of the waste plastic collected is efficiently recycled, while the rest is incinerated, disposed in landfills, or can end up in compost and be released in the environment, inducing a very negative effect on safety and health of flora and fauna. Sustainable management of hardly recyclable plastic waste generated by light weight single use packaging and agricultural films can be improved by applying biotechnological approaches, combining microorganisms, new enzymes, earthworms, and insects to work collaboratively, not only to promote the degradation of these plastics but also to obtain, by-products of the biodegradation process to be valorized as fertilizers, functional polysaccharides, etc. In order to develop a feasible process, mapping and characterization of the most diffused agri-food waste plastic were conducted isolating the main types of plastic involved. Plastic waste in agriculture is mainly constituted by polyethylene (PE) both linear low density (L...
Rhynchophorus ferrugineus (Olivier, 1790) is an invasive pest species that constitutes one of the... more Rhynchophorus ferrugineus (Olivier, 1790) is an invasive pest species that constitutes one of the most important problems around the Mediterranean region and has been responsible for the loss of over 100,000 palm trees with an estimated annual cost of EUR several hundred million since its introduction into Europe. Methodological approaches of conservation ecology, such as multidisciplinary modelling, also apply in the management of cultural landscapes concerning ornamental plants, such as palm trees of the area. In this paper, we propose a dynamic model for the control of the red palm weevil, contributing in this way to the sustainability of an existing cultural landscape. The primary data set collected is a sample from the density-time function of a two-cohort pest population. This data set suggests a bimodal analytic description. If, from this data set, we calculate a sample from the accumulated density-time function (the integral of the density-time function), it displays a doubl...
We propose a conceptual model for pollination and fertilization of tomato flowers in greenhouses ... more We propose a conceptual model for pollination and fertilization of tomato flowers in greenhouses crops by hoverflies, when the maximal number of adult pollinators maintained by the crops is less than what is needed for an economically successful pollination in greenhouses. The model consists of a two-stage process for additional feeding of hoverfly to maintain the pollinator density at the economically desired level. First, with a stochastic model, we calculate the density of flies necessary for the economically successful pollination, determined according to the economically expected yield. Second, using a deterministic optimal control model, we find a minimum cost supplementary feeding strategy. In summary, we theoretically demonstrate, at the present stage of the research without validations in case studies, that optimal supplementary feeding can maintain the economically desired hoverfly density.
Although a large number of pesticides of different compositions are regularly used in agriculture... more Although a large number of pesticides of different compositions are regularly used in agriculture, the impact of pesticides on the physiology of field crops is not well understood. Pesticides can produce negative effects on crop physiology―especially on photosynthesis―leading to a potential decrease in both the growth and the yield of crops. To investigate these potential effects in greenhouse sweet peppers, the effect of 20 insecticides and 2 fungicides (each sprayed with a wetting agent) on the photosynthesis of sweet pepper leaves was analyzed. Among these pesticides, nine caused significant reductions in photosynthetic activity. The effects were observed in distinctive ways—either as a transitory drop of the photosynthetic-rate values, which was observed at two hours after the treatment and was found to have recovered after 24 h, or as a sustained reduction of these values, which remained substantial over a number of days. The results of this study suggest that the production of...
The South American Tomato Pinworm, Tuta absoluta (Meyríck) causes important damages ín tomate cro... more The South American Tomato Pinworm, Tuta absoluta (Meyríck) causes important damages ín tomate crops in Spain; nevertheless, the damages are dífferent in open air crops, spríng - summer cycle, with constant and increasing infestations by overlap populations; respect to greenhouse crops, autumn - spring cycle, ín that the attacks take place at first and at the end of the crop cycle and that originate from discreet populations. Therefore, the control methods, according to the kind of crops, must be different; also, the varieties used in every case are different. For it, the aim of this work was to study the influence of the cultivated host plant on the efficiency and activity of biological control agents. The works were carried out in a greenhouse (1,000 m2), transplanted with plants of 5 tomate varieties, more representative of two types of crops, as mentioned befare: Razymo® Rijk Zwaam, Realeza® Ruiter Semillas, Tovi Star® Zeraim Ibérica, Tyty® Syngenta Seed and Vernal® Enza Zadem; t...
In Western Europe, including Southern Europe to Greece, four Noctuid species, belonging to the co... more In Western Europe, including Southern Europe to Greece, four Noctuid species, belonging to the corn earworm complex, are quite common: Helicoverpa armigera Huebner, Heliothis peltigera Schiffermueller, Heliothis viriplaca Hufnagel, and Heliothis nubigera Herrich Schaefer, the last in Spain and Portugal. H. armigera is the most destructive of them in Southern Europe, causing economically significant crop losses on corn, tomato, cotton, tobacco and many other host plants.A summary of the data on biology, migration and seasonal occurrence on several crops is presented for Heliothis spp. Parasitoids and predators are presented, as well as host plants. The establishment of a European Workshop on Heliothis spp. is mentioned. The concerned research centers are presented, with their main work on the pest and its host plants, and research on parasitoids, rearing techniques and release.
For the monitoring of population systems, mathematical systems theory offers an efficient method.... more For the monitoring of population systems, mathematical systems theory offers an efficient method. The concept of observability can guarantee at theoretical level the possibility of recovering the time- dependent state of a whole population system from the observation of the certain components. Once local observability near an existing equilibrium is proved, we also need a constructive method for the estimation of the state process. To this end an auxiliary system, the so-called observer system can be applied. The latter is constructed from the observed data, and asymptotically estimates the complete state process with exponential speed of convergence. The methodology used for the construction of the observer system is based in the observer design of Sundarapandian. For the illustration of this methodology, a population system modeling the biological control of the sugarcane borer (Diatraea saccharalis) by the egg parasitoid Trichogramma galloi and the larvae parasitoid Cotesia flavi...
The beet armyworm, Spodoptera exigua, is a highly polyphagous insect pest that affects various ag... more The beet armyworm, Spodoptera exigua, is a highly polyphagous insect pest that affects various agricultural crops including vegetables and ornamentals. It is a serious pest in several greenhouse crops, including pepper and watermelon. In turn, the predator Nabis pseudoferus, a member of the Nabidae family, is a strictly zoophagous species that is commercially available in Spain. Several trials were carried out on the biology and ecology of the pest and predator species in pepper crops grown in southern Spain, under both laboratory and greenhouse conditions. This work describes trials to evaluate the efficacy of the predator species for controlling different levels of pest infestation in commercial pepper greenhouses. With the resulting data, a degree-day dependent and stage-structured dynamic mathematical model for predator-prey systems was developed and validated. From the results, it can be seen that the “degree of depression” found in the prey population between the first and sec...
The classical Holling type II functional response, describing the per capita predation as a funct... more The classical Holling type II functional response, describing the per capita predation as a function of prey density, was modified by Beddington and de Angelis to include interference of predators that increases with predator density and decreases the number of killed prey. In the present paper we further generalize the Beddington-de Angelis functional response, considering that all predator activities (searching and handling prey, fight and recovery) have time duration, the probabilities of predator activities depend on the encounter probabilities, and hence on the prey and predator abundance, too. Under these conditions, the aim of the study is to introduce a functional response for fighting the predator and to analyse the corresponding dynamics, when predator-predator-prey encounters also occur. From this general approach, the Holling type functional responses can also be obtained as particular cases. In terms of the activity distribution, we give biologically interpretable suffi...
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