José Roberto Postali Parra

Trichogramma in Brazil: feasibility of use after twenty years of research

Results of studies with Trichogramma in Brazil are presented, especially those developed at ESALQ/USP in the past two decades (1984-2004). The project involved taxonomy, rearing techniques, biological and behavioral aspects of the pests and parasitoids, pest population dynamics, release techniques, selectivity studies, and efficiency evaluation. It can be considered a model project and has been adopted by other biological control programs in Brazil and Latin America. The program has given rise to a number of publications, allowing the formation of human resources in this area and opening new research areas. The results indicated that the parasitoid can be used to control key pests in cotton, sugarcane, stored grain, vegetables, corn, soybean, and tomato. The perspective of using the parasitoid has stimulated the creation of companies to commercialize it in Brazil, thus more easily transferring this technology to users.

Do new Access and Benefit Sharing procedures under the Convention on Biological Diversity threaten the future of biological control

Under the Convention on Biological Diversity (CBD) countries have sovereign rights over their genetic resources. Agreements governing the access to these resources and the sharing of the benefits arising from their use need to be established between involved parties [i.e. Access and Benefit Sharing (ABS)]. This also applies to species collected for potential use in biological control. Recent applications of CBD principles have already made it difficult or impossible to collect and export natural enemies for biological control research in several countries. If such an approach is widely applied it would impede this very successful and environmentally safe pest management method based on the use of biological diversity. The CBD is required to agree a comprehensive Access and Benefit Sharing process in 2010, in preparation for which the IOBC (International Organization for Biological Control of Noxious Animals and Plants) Global Commission on Biological Control and Access and Benefit Sharing has prepared this position paper. Here, we first describe the practice of biological control in relation to the principles of ABS, illustrated extensively by case studies and successes obtained with biological control. Next, we emphasise the very limited monetary benefits generated in biological control when compared to other fields of ABS such as the collection of germplasm for development of human drugs, chemical pesticides or crop cultivars. Subsequently, we inform the biological control community of good ABS practice and challenges, and we hope to make clear to the community involved in ABS under the CBD the special situation with regard to biological control. Finally, based on the non-commercial academic research model, we make recommendations which would facilitate the practice of collection and exchange of biological control agents, propose a workable framework to assist policy makers and biological control practitioners, and urge biological control leaders in each country to get involved in the discussions with their national ABS contact point to take their needs into consideration.

Side‐effects of insecticides used in tomato fields on the egg parasitoid Trichogramma pretiosum Riley (Hym., Trichogrammatidae), a natural enemy of Tuta absoluta (Meyrick) (Lep., Gelechiidae)

Abstract: Trichogramma pretiosum Riley is an important natural enemy used for the biological control of Tuta absoluta in tomato fields in several countries in South America. The side‐effects of insecticides on T. pretiosum was tested by dipping parasitized host eggs (Ephestia kuehniella Zeller) at three different development stages (egg‐larvae, pre‐pupae and pupae) in pesticide solution at recommended concentrations. The insecticides varied in their toxicity and significantly affected the development time of the immature stages, emergence, parasitism and longevity of the adult parasitoid. Cartap and phenthoate were harmful and caused total mortality in all the experiments in the three stages of development tested. Lambda‐cyhalothrin was not detrimental but caused a significant increase in mortality, prolonged development of the immature stages and decreased the capacity of parasitism of the emerged females. Tebufenozide, teflubenzuron and abamectin had sublethal effects. They reduced the time of development, especially when applied during the pupae stage. The capacity of parasitism of emerged females decreased and was affected by the stage of development treated. With abamectin treatments, parasitism decreased as the development of the parasitoid advanced and the mortality of the emerged adults from host eggs treated during the pupae stage was significantly higher. Tebufenozide reduced parasitism when applied during the egg‐larval and pre‐pupae stages. The results showed that cartap and phenthoate were harmful, lambda‐cyalothrin and abamectin were intermediate, tebufenozide and teflubenzuron were harmless to slightly harmful. Nearly all the chemicals tested had significant sublethal effects.

Biology of Diaphorina citri (Hem., Psyllidae) on different hosts and at different temperatures

Abstract:  The objective of this work was to study the effect of different hosts and temperatures on Diaphorina citri Kuwayama (Hem., Psyllidae) biology. Citrus limonia (Rangpur lime), Murraya paniculata (orange jessamine) and Citrus sunki (Sunki mandarin) were used as hosts. Measurements included duration and viability of the egg and nymphal stages, sex ratio, fecundity and longevity. In order to verify the effect of temperature on D. citri biology, the duration and viability of its developmental stages and biological cycle were compared at seven different temperature conditions. Durations of the embryonic and nymphal stages were similar for Rangpur lime, orange jessamine and mandarin. However, the nymphal viability obtained on mandarin was lower than the values obtained on the other hosts. Fecundity was higher on orange jessamine and, in all instances, females had greater longevity than males. A fixed number of instars (five) was obtained on the three hosts. Rangpur lime and orange jessamine provided better D. citri development when compared with mandarin. Duration of the egg and nymphal stages varied from 2.6 to 7.7 and from 9.4 to 35.8 days, respectively, at temperatures from 18 to 32°C. Egg viability was higher than 81.6% at the temperature range studied (18–32°C); nymphal viability was higher than 70% at the 18–30°C range, differing from viability at 32°C, which was dramatically reduced. The D. citri lower temperature development threshold (TT) and thermal constant (K) values for the egg, nymphal and biological cycle (egg–adult) stages were 12.0°C and 52.6 Degree‐Day (DD); 13.9°C and 156.9 DD; and 13.5°C and 210.9 DD respectively.

Adaptation of tobacco budworm Heliothis virescens to proteinase inhibitors may be mediated by the synthesis of new proteinases

The tobacco budworm Heliothis virescens is adapted to feed on tobacco leaves that have proteinase protein inhibitors (PIs). To study this adaptation, the midgut proteinases of Heliothis virescens larvae reared on artificial PI-free diet and on tobacco leaves were compared using ion exchange chromatography, hydrophobic chromatography, gel filtration and polyacrylamide gel electrophoresis at different conditions. SDS polyacrylamide-gradient gel electrophoresis (SDS-PAGE) and kinetic studies shown that leaf-fed larvae have a chymotrypsin (M(r) 26000) and four trypsins (T1-T4) with the following properties: T1, K(m) 0.3 microM, M(r) 70000; T2, K(m) 0.4 microM, M(r) 67000; T3, K(m) 2.4 microM, M(r) 29000; T4, K(m) 15 microM, M(r) 17000. Diet-fed larvae have a chymotrypsin (M(r) 26000) and a major trypsin (K(m) 2.9 microM, M(r) 29000). Native PAGE at different gel concentrations showed that in these conditions, only T1 and T2 occur in leaf-fed larvae, whereas gel filtration in the absence and presence of SDS revealed that T1 and T2 might arise by polymerization of T3 and T4, respectively. The data suggest that, in the presence of PI-containing food, H. virescens larvae express new trypsin molecules that form oligomers and are apparently less affected by PIs because of tighter binding to the substrate (lower K(m) values) and a putative decreased affinity for PIs.

Selectivity of insecticides to the egg parasitoid Trichogramma galloi Zucchi, 1988, (Hym., Trichogrammatidae)

Trichogramma galloi Zucchi is an efficient biological control agent against the sugarcane borer, Diatraea saccharalis (F.) in sugarcane fields in Brazil. This parasitoid is also a candidate to be used in pest management programmes in corn, as D. saccharalis has become a serious pest of this crop in some areas in Brazil. However, there is no data on the side‐effects of chemicals on this species. The side‐effects of promising chemicals to control the sugarcane borer in corn were tested by dipping eggs of the factitious host into the insecticidal solutions. Two different treatments were tested. First, dipping parasitized host eggs at different stages of immature development (egg‐larva, prepupa and pupa); and second, by offering treated eggs to newly emerged females. The toxicity of the chemicals tested were dependent on the age of the parasitoid, affecting the immature survival, developmental time from egg to adult, parasitization capacity, adult longevity and the development of the filial generation. Spinosad, tebufenozide, triflumuron and lufenuron delayed adult eclosion of T. galloi when used to treat the host egg during the pupal stage. Spinosad was harmful when tested against any immature stage and adults of T. galloi. Lufenuron and triflumuron were harmful only when applied during the egg‐larval development of the parasitoid. Although they did not affect the parasitization capacity, they caused almost 100% mortality of the immatures when used to treat eggs prior to parasitization. Tebufenozide was harmless to T. galloi causing a very slight immature mortality if used during the prepupal development.

Effects of soybean proteinase inhibitor on development, survival and reproductive potential of the sugarcane borer, Diatraea saccharalis

One approach that can be employed in integrated pest management is the use of proteins with antinutritional effects on insect metabolism and development. The antimetabolic properties of soybean proteinase inhibitor (SPI) on growth of neonate larvae of the sugarcane borer, Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) have been evaluated. When incorporated into an artificial diet at 0.5% (w/w), SPI retarded growth rate and development of larvae when compared with larvae fed on artificial diet alone. However, larval survival was not significantly affected. The purpose of our research was to calculate demographic statistics for the sugarcane borer reared on diet either with or without semi‐purified extract of SPI. Net reproductive rate (R0), instantaneous rate of increase (rm), combined age‐specific survivorship (lx) and age specific fecundity (mx) provide information about population growth potential. These parameters were measured in order to determine the effects of the proteinase inhibitor on the insects population dynamics. The observed differences would potentially translate into large reductions in population growth, indicating a potential value of using SPI for protecting sugarcane plants against damage by the sugarcane borer.

Egg parasitoids in agroecosystems with emphasis on Trichogramma

1. Reproduction and Immature Development of Egg Parasitoids Guy Boivin.- 2. Nutritional Ecology of Insect Egg Parasitoids S. Bradleigh Vinson.- 3. Antennal Structures Used in Communication by Egg Parasitoids Roberto Romani, Nunzio Isidoro, Ferdinando Bin.- 4. Host Searching by Egg Parasitoids: Exploitation of Host Chemical Cues Stefano Colazza, Ezio Peri, Gianandrea Salerno, Eric Conti.- 5. Genetics of the Behavioral Ecology of Egg Parasitoids Eric Wajnberg.- 6. Sex Ratio Modulators of Egg Parasitoids James Russell, Richard Stouthamer.- 7. Systematics of the Trichogrammatidae (Hymenoptera: Chalcidoidea) with a Focus on the Genera Attacking Lepidoptera Ranyse B Querino, Roberto A Zucchi, John D. Pinto.- 8. Diversity and hosts of Trichogramma in the New World, with emphasis in South America Roberto A Zucchi, Ranyse B Querino, Renata C Monteiro.- 9. Species Diversity and Host Associations of Trichogramma in Eurasia Andrew Polaszek.- 10. Mass Rearing of Egg Parasitoids for Biological Control Programs Jose Roberto Postali Parra.- 11. In vitro Rearing of Egg Parasitoids Fernando L Consoli, Simon Grenier.- 12. Quality Control of Mass Reared Egg Parasitoids Joop C. van Lenteren, Franz Bigler.- 13. Biological Control with Egg Parasitoids other than Trichogramma - the Citrus and Grape Cases Jorge E. Pena, Josep A. Jacas, Serguei Tryapsin, Bryan J. Ulmer, R. E. Duncan.- 14. Egg Parasitoid Commercialization in the New World Jose Roberto Postali Parra.- 15. Egg Parasitoids in Biological Control and Integrated Pest Management Nick Mills.- 16. Risk Assessment and Non-Target Effects of Egg Parasitoids in Biological Control Franz Bigler, Dirk Babendreier, Joop C. van Lenteren.- 17. Genetically Modified Crops and Biological Control with Egg Parasitoids Julio S Bernal.

Changes in midgut endopeptidase activity of Spodoptera frugiperda (Lepidoptera: Noctuidae) are responsible for adaptation to soybean proteinase inhibitors.

Abstract The development of transgenic maize plants expressing soybean proteinase inhibitors could reduce the economic damage of one of the major maize pests in Brazil, the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797). We examined the influence of soybean proteinase inhibitors on digestive enzyme properties and development of S. frugiperda larvae. The inhibition of trypsin and chymotrypsin activities in vitro by soybean proteinase inhibitors suggested that either Kunitz (SBTI) or Bowman-Birk (SBBI) would have a potential antimetabolic effect when ingested by insect larvae. However, chronic ingestion of semipurified soybean inhibitors did not result in a significant reduction of growth and development of fall armyworm. Therefore, digestive serine proteinase activities (trypsin and chymotrypsin) of fall armyworm larvae were characterized. The results suggest that S. frugiperda was able to physiologically adapt to dietary proteinase inhibitors by altering the complement of proteolytic enzymes in the insect midguts.

Ultrastructure of the natural and factitious host eggs of Trichogramma galloi Zucchi and Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

Abstract The surface and structure of the chorion of eggs of Diatraea saccharalis (F.) (Lepidoptera: Crambidae), Anticarsia gemmatalis (Huebner), Heliothis virescens F., Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), Sitotroga cerealella (Oliver) (Lepidoptera: Gelechiidae), Ephestia kuehniella Zeller and Corcyra cephalonica Stainton (Lepidoptera: Pyralidae), that are hosts of Trichogramma galloi Zucchi and Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) were studied on SEM and TEM. Other characteristics of these eggs, such as changes in their color during embryonic development, size and volume were also recorded. Sculpturing and texture of the surface of the chorion greatly varied among the species studied, as well as the number of layers of the chorion and their thickness. Eggs of the factitious hosts were among the smallest and their volume was very close to each other. All these characteristics would provide basic information for a better understanding of the host selection behavior and are useful for the development of a suitable artificial host egg for the in vitro rearing of these egg parasitoids.