2011 CORESTA AGRO-PHYTO MEETING

Transcription

1 2011 CORESTA AGRO-PHYTO MEETING Spatial distribution and impact of adjacent vegetation on families of parasitic hymenoptera associated with organic tobacco in Santa Cruz do Sul, RS, Brazil CECÍLIA DORFEY (JTI Kannenberg) Dr. ANDREAS KÖHLER (Unisc) KARINE SCHOENINGER (Unisc) Santiago, Chile November 9 th 2011

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4 INTRODUCTION The organic agriculture has a systemic approach that gives special attention to the environment preservation, to the agro biodiversity, to the biogeochemical cycles and the human quality of life. (RICCI, 2006) The organic cultivation uses the natural elements and the available biodiversity in combination with new perceptions and excludes the use of agrochemicals. The transition of a conventional agriculture to an organic one is based on a gradual process of changes in the agro ecosystem management. (KARNOPP, 2005) Therefore, the protection of crops against organisms that are occasionally harmful pathogens, pests and weeds is particularly taken into consideration when developing a more sustainable production due to the costs involved and the unfavorable effects to the food chain and biological/ecological balance.

5 INTRODUCTION The search for alternative methods for controlling pests that are compatible with the organic production, in accordance to the integrated pest management (IPM) approach such as biological control has become more relevant. (ONODY, 2009) Results from experiments aiming to avoid or reverse the negative consequences of agrochemical utilization and management practices in modern agro ecosystems indicate that the biodiversity can be used to improve pest management. (ALTIERI, SILVA & NICHOLLS, 2003)

6 INTRODUCTION The biodiversity is crucial to crop protection The greater the diversity of plants, animals and organisms in an agricultural system the greater the diversity of the community of natural enemies of pests in this system (Nicholls and Altieri, 2007) (Altieri, 1999)

7 INTRODUCTION Thus, the development of technologies and agroecological systems that emphasize the conservation and/or regeneration of the biodiversity, the soil, the water and other resources is urgently necessary to reach the socio-economical and environmental challenges in crop production, specially within the context of those under organic management. Increasing the functional biodiversity in agroecosystems is a key strategy to bring environmental sustainability to production

8 INTRODUCTION The knowledge and conservation of the relationships between the organisms existing in a tri-trophic system Plant + herbivore + natural enemy such as the agro ecosystem serves not only to maintain the dynamics of the natural ecosystem but also can be economically used in controlling pests. Once the so-called sustainable, productive and environmental balanced agriculture is based in practices that promote the biodiversity and the natural biological processes, it is inferred that the biological control in all its context is a promising alternative to pest management in sustainable agro ecosystems.

9 INTRODUCTION The natural occurrence of parasitoids in crops is a major factor in reducing pest infestation and the knowledge of this fauna, as well as the conservation of the environment, nesting sites and food resources of these insects become extremely important to increase the effectiveness of biological control.

10 INTRODUCTION Conservation biological control suggests the maintenance of the native natural enemies (parasitoids) in agro ecosystem through agronomic practices environment manipulation - in order to offer better conditions of survival and reproduction (shelter, microclimate, pollen, alternative hosts, etc)

11 INTRODUCTION Edge effect on biodiversity the degree of diversity of vegetation in and around the production unit, the amount of crops that make up the rotation, the proximity to a forest, the existence of hedgerows and pastures or other forms of natural vegetation are factors that contribute to the level of biodiversity in an agricultural unit Nicholls and Altieri (2007)

12 INTRODUCTION Edge effect on biodiversity Langellotto and Denno (2004) Pfiffner and Wyss (2004) when the structure of the habitat is increased there is also an increase in the abundance of natural enemies thus, the provision of resources through flowers and herbs which are distinct from the main crop contributes to the abundance of parasitoids through the availability of pollen or nectar. The cultivation of wild flowering plants in rows can increase population levels of herbivores, providing food resources for the growing population of natural enemies. This technique benefits the natural enemy in times of shortage of prey in the culture, as in early development or after harvest. This benefit is important to control the pest, particularly if natural enemies are generalists and are more abundant in the early stages of crop development

13 OBJECTIVES To assess the spatial distribution of Hymenoptera parasitoids associated to tobacco under organic management To evaluate the effect of the presence of adjacent vegetation on populations of parasitoids.

14 METHODOLOGY Tobacco Field Area: 160 x 85 m Organic Certification CEE 2092/91 (EU) USA NOP 7 CFR Part 205 (USA National Organic Program)

15 METHODOLOGY

16 METHODOLOGY Sampling Period to to samples - Once per week Identification and Registering Taxonomic Identification (Goulet & Huber, 1993) Microscope alcohol 70% + 2% formalin Entomological Collection of Santa Cruz (CESC)

17 METHODOLOGY Statistical Analysis Faunistic Analysis Frequency, Dominance, Constancy Faunistic Indexes Shannon (Diversity) Equitability (J) Cluster Analysis Bodenheimer (1955) apud Ribeiro (2005), Dajoz (1978), Krebs (1978), Ludwig e Reynolds (1988); Palissa et al. (1979) apud Ott (1997), Silveira Neto et al. (1976), Uramoto, Walder e Zucchi (2005).

18 RESULTS AND DISCUSSION Parasitic Hymenoptera 33 families 10 Superfamilies 87% Ichneumonoidea Chalcidoidea Ichneumonidae Eucoilidae Braconidae Scelionidae Mymaridae Eulophidae Encyrtidae Bethylidae

19 RESULTS AND DISCUSSION Frequency of parasitic Hymenoptera Ichneumonoidea Chalcidoidea Cynipoidea / /10 Ichneumonoidea Chalcidoidea Platygastroidea Ichneumonidae (28,70%) Braconidae (28,14%) Eucoilidae (11,13%) Scelionidae (7,60%) Scelionidae (16,40%) Ichneumonidae (15,65%) Eucoilidae (15,15%) Braconidae (12,40%)

20 RESULTS AND DISCUSSION Constancy (2008/2009 e 2009/2010) Constant Acessory Permanent fauna associated to tobacco Adaptability to the environment of the culture Dominance (2008/2009 e 2009/2010) Subdominant Dominant Encyrtidae Eulophidae Mymaridae Bethylidae Dominant Scelionidae Eudominant Ichneumonidae Braconidae Eucoilidae

21 RESULTS AND DISCUSSION Comparison between crop years: By location of sampling points OUTSIDE BORDER INSIDE 2008/ / / / / /2010 Families Individuals Shannon 2,31 2,44 2,19 2,45 1,70 2,34 Equitability J 0,68 0,70 0,64 0,71 0,51 0,69 Similar distribution of individuals in both crop years, except the Inside Beneficial arthropods move to crop fields from the marginal areas and the biological control is more intense in plant lines closer to the wild vegetation. To complete their life cycles, parasitoids need refuge and food alternatives, besides hosts. Wild fences and different vegetation in the field margins may serve as natural enemies reservatories.

22 RESULTS AND DISCUSSION Comparison between crop years: By location of sampling points OUTSIDE BORDER INSIDE 2008/ / / / / /2010 Families Individuals Shannon 2,31 2,44 2,19 2,45 1,70 2,34 Equitability J 0,68 0,70 0,64 0,71 0,51 0,69 * * Higher number of individuals collected in the border in both crop years: Preference of parasitoids in organic tobacco (in the case of this research) for areas of transition between the monoculture and border composed by other plant species. Presence of adjacent vegetation composed by trees and shrubs next to lines 1 and 2 gives the environment a higher diversification in structure and consequently influences the dynamic of spatial distribution of parasitoids to the inside of the crop field. * Lower # individuals but more similar diversity = better distribution of parasitoids into families

23 RESULTS AND DISCUSSION Comparison between crop years: By location of sampling points The management and maintenance of areas of native vegetation around crop fields may be an excellent strategy of biological control, as it does not implies costs with importation, missal creation and release of natural enemies, and at the same time contributes to the native fauna of parasitoids. Europe studies affirm that the practice of establishment of flowering plant corridors increases the diversity and quantity of natural enemies. The higher diversity and equitability for the Outside and Border sampling points in both seasons reflects the environment conditions with the preservation of plant species that differ from the main crop.

24 RESULTS AND DISCUSSION Comparison between crop years: By sampling line L1 L2 L3 2008/ / / / / /2010 Families Individuals Shannon 2,24 2,41 2,18 2,46 1,58 2,39 Equitability 0,66 0,69 0,63 0,71 0,48 0,73 L1 sampling line with border area 10-15m wide, composed by tree species of medium to large size; L2 line with border area 3-5m wide, composed by tree species of smaller size; L3 line with border area composed by grass and plants of spontaneous growth. In both crop years: Sampling line 1: higher abundance Outside Sampling line 2: higher abundance Border Sampling line 3 : changed distribution among the three sampling points. Lines 1 and 2 are more similar to each other in both harvests, and the values for line 3 are inferior when compared to these lines. Landscape differentiation may have contributed to the insect distribution once the absence of adjacent vegetation did not provide shelter, food and alternative hosts to parasitoids, as well as for line 3 being more exposed to environment and climate conditions (wind, sun exposure ) + Ichneumonidae (57%)

25 Not removal of spontaneous growth plants and planting vetch (Vicia villosa Roth) and radish (Raphanus sativus Linnaeus) as well as elephant grass (Pennisetum purpureum Schum.) for barrier against the wind

26 RESULTS AND DISCUSSION Comparison between crop years: By sampling line L1 L2 L3 2008/ / / / / /2010 Families Individuals Shannon 2,24 2,41 2,18 2,46 1,58 2,39 Equitability 0,66 0,69 0,63 0,71 0,48 0,73 L1 sampling line with border area 10-15m wide, composed by tree species of medium to large size; L2 line with border area 3-5m wide, composed by tree species of smaller size; L3 line with border area composed by grass and plants of spontaneous growth. Greater similarity between indexes General reduction in the number of individuals sampled Better distribution of Ichneumonidae (28%) Presence of spontaneous growth vegetation = better distribution of parasitoids

27 RESULTS AND DISCUSSION Comparison between crop years: By sampling line L1 L2 L3 2008/ / / / / /2010 Families Individuals Shannon 2,24 2,41 2,18 2,46 1,58 2,39 Equitability 0,66 0,69 0,63 0,71 0,48 0,73 L1 sampling line with border area 10-15m wide, composed by tree species of medium to large size; L2 line with border area 3-5m wide, composed by tree species of smaller size; L3 line with border area composed by grass and plants of spontaneous growth. Stage of plant succession influences the distribution of parasitoids L1 e L2 different from L3 Tress and shrubs differ from grasses and smaller size plant species

28 Similarity Similarity L3 L2 L1 L3 L2 L1 L3 L2 L1 L3 L2 L1 RESULTS AND DISCUSSION Spontaneous plants inside and around crops influence the dynamics in agriculture and biotic communities associated. However, habitats in more advanced stage of succession (such as trees and shrubs) generally result in higher diversity of parasitoids than herbs and monocots (HAWKINS & LAWTON, 1987). 0,98 0,975 0,96 0,95 0,94 0,925 0,9 0,92 0,875 0,9 0,85 0,88 0,825 0,86 0,8 0,775 0,84 0 0,4 0,8 1,2 1,6 2 2,4 2,8 3,2 3, ,4 0,8 1,2 1,6 2 2,4 2,8 3,2 3, / /2010

29 Similarity L3B (09.10) L3D (09.10) L3F (09.10) L1D (09.10) L2B (09.10) L2F (09.10) L2D (09.10) L1F (09.10) L1B (08.09) L2F (08.09) L1F (08.09) L2D (08.09) L1B (09.10) L2B (08.09) L3F (08.09) L3B (08.09) L1D (08.09) L3D (08.09) RESULTS AND DISCUSSION 0,96 0,92 0,88 0,84 0,8 0,76 0, Dendogram of similarity between sampling lines and sampling points, with respect to the fauna of parasitoids associated to tobacco under organic management, in Santa Cruz do Sul, RS, Brazil, in the 2008/2009 (08.09) and 2009/2010 (09.10) crop years. L: line, F: Outside, B: Border, D: Inside

30 Similarity L3B (09.10) L3D (09.10) L3F (09.10) L1D (09.10) L2B (09.10) L2F (09.10) L2D (09.10) L1F (09.10) L1B (08.09) L2F (08.09) L1F (08.09) L2D (08.09) L1B (09.10) L2B (08.09) L3F (08.09) L3B (08.09) L1D (08.09) L3D (08.09) RESULTS AND DISCUSSION 0,96 0,92 0,88 0,84 0,8 0,76 0, Dendogram of similarity between sampling lines and sampling points, with respect to the fauna of parasitoids associated to tobacco under organic management, in Santa Cruz do Sul, RS, Brazil, in the 2008/2009 (08.09) and 2009/2010 (09.10) crop years. L: line, F: Outside, B: Border, D: Inside

31 FINAL CONSIDERATIONS The families Ichneumonidae, Braconidae, Eucoilidae and Scelionidae are the most frequent associated to organic tobacco, as well as chalcidoids (Mymaridae, Eulophidae and Encyrtidae). Areas in the outside and border of the tobacco field show higher numbers of individuals when compared to the inside of the field. Preference of parasitoids for areas of transition between cultures.

32 FINAL CONSIDERATIONS Sampling points Outside, Border and the sampling lines where adjacent area is composed by species of shrubs and trees of medium and large size higher diversity of parasitoids and homogeneous distribution of natural enemies within the families sampled in these locations. Presence of adjacent vegetation of spontaneous growth contributes to higher diversity of parasitoid families in organic tobacco field, as well as for a better distribution of individuals (higher equitability)

33 THANK YOU FOR YOUR ATTENTION! Cecília Dorfey Agronomy Department JTI Kannenberg Comércio de Tabacos do Brasil Ltda. A Member of the JTI Group of Companies cecilia.dorfey@jti.com