Biological Control

Endophytic fungi isolated from açaí leaflets (Euterpe precatoria)

The file contains all data used in the manuscript.

It is important to develop efficient and cost-effective methods for monitoring the establishment and fitness of biological control agents. Understanding how simple and obtainable measurements of insects or their body parts relate to reproductive life-history traits could facilitate assessing the fitness of biological control agent populations in the field. Across many insect taxa, female size represents a principal constraint on potential fecundity. Here, we investigate the relationship between pupal measurements and aspects of potential fecundity in Hypena opulenta (Lepidoptera: Erebidae), a recently released biological control agent against Vincetoxicum rossicum and V. nigrum (Apocynaceae) in Ontario Canada. We dissected adult H. opulenta females of different ages to assess their strategy of oogenesis by counting and measuring the number of eggs in their ovarioles and establishing the relationship between pupal measurements and potential fecundity. A second experiment was conducted to determine the relationship between pupal weight and adult longevity. While moths emerged with eggs in their ovarioles, oogenesis continued throughout the adult stage, and mean egg size increased with time after emergence. These observations place the moth closer to being an income breeder on the ovigeny index scale. We observed no significant relationship between pupal weight and total number of eggs; however, pupal weight was positively correlated with adult longevity. These results demonstrate the limited use of general size-fecundity relationships in post-release assessments for insects that are income breeders. However, they also highlight how the understanding of reproductive strategy in H. opulenta can provide important information to aid in its establishment and spread at release sites.

Input data used in the simulations ran for the specific case study. It contains data on temperature, relative humidity (RH) and intensity of flushing for 54 locations in the state of São Paulo, Brazil.

The complete computational code that was developed with the R software (R Development Core Team, 2008) to calculate the Fuzzy index. Please use the file example.csv as input file.

Data collected by the Laboratory of Insect Biology of the Entomology and Acarology Department, Luiz de Queiroz College of Agriculture, University of São Paulo (USP-ESALQ)

METHODOLOGICAL INFORMATION 1. Description of methods used for collection-generation of data: For the direct and fumigant lethal effect, data were collected by observing the number of nematodes that die when exposed to three different essential oils. The objective was to determine if the three esential oils are compatible with nematodes observing the mortality caused by them. For the infectivity sublethal effect, data were collected by oberving the infectivity and reproduction of nematodes priously exposed to three essential oils. The objective was to determine if nematodes exposed to essential oils that do not die present sublethal effects due to their exposure to these oils. For the chemotaxis assay, the number of nematodes that displaced to the treated (essential oil) or control areas was counted. Then, the chemotaxis index was calculated for each product tested. The objective was to determine if nematodes are attracted or repelled by the volatiles emitted by the essential oilsdifferent volatile organic compounds emmited by truffles 3. Software specific information needed to interpret the data: Program R (4.3.1 version) for statistical analysis. A linear model (LM) or a linear mixed model (LMM) (when the exposure time factor was considered) was used, with an arcsine square root transformation of the data, to test for significant differences in the mortality of EPNs in the lethal effect assays. A linear model (LM) was also applied to compare the chemotaxis response of EPNs to the EOs. For the sublethal effect assay, a generalized linear model (GLM), with binomial distribution and a logit link function, was used to test for significant differences in the infectivity of EPNs. 5. Environmental or experimental conditions: Experimental conditions

Program R, 4.1.0

Arundo donax is a non-native, invasive large-statured grass of riparian systems in the southwestern U.S.A., including the Sacramento and San Joaquin River watersheds of northern California and the Sacramento-San Joaquin Delta. In 2017, the shoot tip-galling wasp Tetramesa romana was released at nine sites, three in each region. Shoots in some release plots were manipulated prior to release by cutting to ground or pruning to 1 m height, while others were left uncut. One year later, exit holes made by emerging adult wasps were found at two of nine sites. Exit hole density per main shoot length was 16-fold higher on regrowth shoots in ground-cut plots than in uncut plots. An additional plot manipulation study at two other sites found that exit hole density per shoot length was 19-fold higher in plots that were double-cut (cut to ground and regrowth pruned) than in single-cut plots. By 2023, T. romana was established at eight sites spanning both river watersheds and their Delta with dispersal up to 6.4 km, based on dissection of shoots, multi-year counts of exit holes and galls, and trapping of adult T. romana with sticky traps. The abundance of T. romana may be limited in northern California by low annual heat unit accumulation. The results show that physical manipulation of host plants improves short-term establishment and demonstrate the importance of using multiple monitoring methods to determine long-term establishment.

Arundo donax is a non-native, invasive large-statured grass of riparian systems in the southwestern U.S.A., including the Sacramento and San Joaquin River watersheds of northern California and the Sacramento-San Joaquin Delta. In 2017, the shoot tip-galling wasp Tetramesa romana was released at nine sites, three in each region. Shoots in some release plots were manipulated prior to release by cutting to ground or pruning to 1 m height, while others were left uncut. One year later, exit holes made by emerging adult wasps were found at two of nine sites. Exit hole density per main shoot length was 16-fold higher on regrowth shoots in ground-cut plots than in uncut plots. An additional plot manipulation study at two other sites found that exit hole density per shoot length was 19-fold higher in plots that were double-cut (cut to ground and regrowth pruned) than in single-cut plots. By 2023, T. romana was established at eight sites spanning both river watersheds and their Delta with dispersal up to 6.4 km, based on dissection of shoots, multi-year counts of exit holes and galls, and trapping of adult T. romana with sticky traps. The abundance of T. romana may be limited in northern California by low annual heat unit accumulation. The results show that physical manipulation of host plants improves short-term establishment and demonstrate the importance of using multiple monitoring methods to determine long-term establishment.