The USA has been actively involved in classical biological control projects against invasive insect pests and weeds since 1888. Classical (importation) biological control relies upon natural enemies ...associated through coevolution with their target species at their geographic origin to also provide long-term, self-sustaining management where the pest/weed has become invasive. Biological control agents are a form of genetic resources and fall under the purview of the 1993 Convention on Biological Diversity (CBD) and its Nagoya Protocol (NP), which entered into force in 2014 to address equitable sharing of benefits arising from utilization of genetic resources. Safe and effective classical biological control agents have historically been shared among countries experiencing problems with invasive species. However, a feature of the Nagoya Protocol is that countries are expected to develop processes governing access to their genetic resources to ensure that the benefits are shared equitably—a concept referred to as “access and benefit sharing” (ABS). Although the USA is not party to the CBD nor the NP, US biological control programs are affected by these international agreements. Surveying, collecting, exporting and importing of natural enemies may be covered by new ABS regulatory processes. Challenges of ABS have arisen as various countries enact new regulations (or not) governing access to genetic resources, and the processes for gaining access and sharing the benefits from these resources have become increasingly complex. In the absence of an overarching national US policy, individual government agencies and institutions follow their own internal procedures. Biological control practitioners in the USA have been encouraged in recent years to observe best practices developed by the biological community for insect and weed biological control.
Determining the most likely source of an invasive pest species might help to improve their management by establishing efficient quarantine measures and heading the search of efficient biological ...control agents. Planococcus ficus is an invasive mealybug pest of vineyards in Argentina, California, Mexico, Peru and South Africa. This mealybug pest had a previously known geographic distribution spanning southern Europe, the Middle East, and parts of northern Africa. In North America, Pl. ficus was first discovered in the early 1990s and soon thereafter in Mexico. To determine the origin of invasive populations in North America, Pl. ficus from California and Mexico were compared with material throughout its presumptive native range in the Mediterranean region, as well as material collected from an older invasion in South Africa and recently invaded Argentina. From each sample location, genomic DNA was sequenced for the nuclear internal transcribed spacer one (ITS1) and the mitochondrial cytochrome c. oxidase one (CO1). Phylogenetic analyses of CO1, ITS1 and concatenated CO1 and ITS1 data-sets using Bayesian and neighbor-joining analysis support two major divisions: a European grouping (Europe, Tunisia, Turkey) and a Middle Eastern grouping (Israel and Egypt). The invasive populations in Argentina and South Africa align with the European group and the invasive populations in North America align with the Middle Eastern group, with one Israel sample aligning closely with the North American clade, suggesting that Israel was the origin of those populations.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Host detection and parasitism by egg parasitoids involve host chemical recognition, spatial overlapping, and the ability to overcome physical barriers. Within the context of importation biological ...control, we examined the potential of
Gryon gonikopalense
(Hym.: Scelionidae), against the stinkbug pest,
Bagrada hilaris
(Hem.: Pentatomidae). Bagrada is invasive in the Americas where it negatively impacts cruciferous cropping systems. Within Pentatomidae, bagrada possesses a unique behavioral trait in that its eggs are oviposited buried. Our study aimed to evaluate the capacity of
G. gonikopalense
to respond to bagrada ovipositional behavior. We showed that
G. gonikopalense
exhibits a well-adapted foraging behavior observed by tracking and successfully parasitizing 2 mm-deep buried bagrada eggs, which was further supported by video recordings. Four conditions of egg detectability by parasitoids (free eggs, naturally buried eggs, and manually buried with disturbed or clean sand) and foraging durations were tested in Petri dishes. The parasitism rate of 100% was obtained after 72hours for both free and naturally buried eggs; a rate of 71% was obtained after 2 h with free eggs. There was no significant difference concerning the parasitoid success rate (< 40%) with manually buried eggs. Our data suggested that host egg detection was based on chemical cues since parasitism success was reduced by up to 20% when eggs were manually buried under a clean substrate or a substrate previously used for oviposition but disturbed.
Gryon gonikopalense
can overcome both the egg detection and physical barrier constituted by the sand to parasitize the pest despite a reduced number of progeny produced.
Biological control of weeds is a globally recognised approach to the management of some of the most troublesome invasive plants in the world. Accidental introductions of agents accounted for all weed ...biological control agent establishments in the European Union until 2010, but these examples include some current or emerging control successes both large and small, from the redistribution of the weevil
Stenopelmus rufinasus
Gyllenhal (Coleoptera: Curculionidae) for the control of small outbreaks of
Azolla filiculoides
Lam. (Azollaceae), to the large scale control provided by the cochineal insect
Dactylopius opuntiae
(Cockerell) (Hemiptera: Dactylopiidae), used against some problematic prickly pears (
Opuntia
spp. (Cactaceae)), and the ragweed beetle
Ophraella communa
LeSage (Coleoptera: Chrysomelidae), against common ragweed,
Ambrosia artemisiifolia
L. (Asteraceae), which are providing benefits to an increasing number of Member States of the European Union. Recent programmes involving the intentional introduction of biological control agents against target weeds including
Fallopia japonica
(Hout.) Ronse Decr. (Polygonaceae),
Impatiens glandulifera
Royle (Balsaminaceae) and
Acacia longifolia
(Andrews) Willd (Fabaceae) show a shift from luck to judgement in the European Union. The inclusion of new weed targets on the European Invasive Species Regulation should lead to a growth in the profile and use of biological control which would be assisted by the publication of any successes from the few intentional introductions covered in this paper.
•Development and reproduction of G. aetherium were optimal between 25 and 35 °C.•G. aetherium could survive in adult stage for several months in winter range of B. hilaris.•Effective biocontrol of B. ...hilaris by G. aetherium in the USA can be expected in Southern California and Arizona.
Environmental temperature is fundamental determinant of insect physiology and behavior, and the success of an importation biocontrol program often relies on the acclimatization capacity of the introduced biocontrol agent. Co-evolved natural enemies of a target pest that share the same climatic range are expected to be suitable candidates for introduction. The stink bug Bagrada hilaris (Burmeister) is an invasive pest in the USA which damages mainly brassica crops in California and other Southwest states. An egg parasitoid from Pakistan, Gryon aetherium Talamas (Hymenoptera: Scelionidae), is currently being evaluated as a classical biocontrol agent. In order to determine the range of temperatures suitable for G. aetherium, its development, reproduction and survivorship were evaluated in the laboratory under eight regimes of constant temperature, ranging from 15 to 40 °C. Gryon aetherium was able to develop successfully between 18 °C (46.9 ± 0.6 d) and 37.5 °C (7.3 ± 0.09 d) with a maximum emergence rate of 95.5 ± 1.9 % at 25 °C. The parasitoid reproduced under all tested temperatures, with maximum fecundity at 30 °C (104.5 ± 21.2 progeny/female). The mean longevity of adult females was 151.3 ± 6.8 days at 15 °C and declined to 4.3 ± 0.3 days at 40 °C. Our results suggest that G. aetherium should establish in the warmest regions of USA, but would not likely control B. hilaris in crucifer crops of the Californian coastal regions where lower temperatures are likely to limit its developmental success.
Invasive alien plant species (IAPs) are causing significant negative impacts on agricultural production, threatened native species and ecosystems, the services they provide and public health thereby ...affecting European biodiversity and its economy. IAPs invade all types of natural and managed habitat and their impacts, through increased numbers and area invaded, are growing exponentially. Current control options in Europe are largely limited to manual and chemical control, which is high cost, short‐term in effectiveness and with regards to chemical control declining in public acceptability. Globally, classical biological control (CBC) is widely and successfully used to manage many IAPs. CBC aims to redress the ecological imbalance caused by the IAPs, generally being released without their natural enemies. The steps are to select, risk assess potential specific natural enemy biocontrol agents of the IAP (from the IAP's native range) and follow regulatory approval prior to releasing them to ecologically suppress their abundance. CBC is not widely used in Europe. Only five active programmes exist. In this paper, we apply an existing framework to develop a ranked list of environmental IAPs named in the EU Regulation on Invasive Species for biocontrol. We used a scoring system based on existing knowledge on the IAPs impacts, the amount of effort needed to deliver a CBC programme targeting them and the feasibility and likelihood of success of such programmes. We identify 16 IAPs in Europe for which CBC has relatively high potential and discuss existing knowledge that can underpin any future investments in such activities against each of these IAPs. The top three species being Pontederia crassipes, Pistia startiotes and Acacia saligna. This research should support decision‐making on the instigation of future CBC programmes against environmental IAPs in Europe. We set this analysis in the context of other operational and regulatory constraints on developing CBC programmes against environmental IAPs in Europe.
The bagrada bug, Bagrada hilaris, is an invasive insect pest in the family Brassicaceae that causes economically important damage to crops. It was originally present in Asia, the Middle East, and ...Africa, and was reported as invasive in the southwestern part of the US, in Chile, and on a few islands in the Mediterranean Basin. In its native range, B. hilaris is controlled by several egg parasitoid species that are under consideration as potential biological control agents. This research evaluated the impact of gamma irradiation on life history parameters, e.g., the fecundity, fertility, and longevity of B. hilaris, as a critical step towards assessing the feasibility of using the sterile insect technique against this recent invasive pest. Newly emerged adults of a laboratory colony originally collected from the island of Pantelleria (Italy) were gamma-irradiated. Life history parameters were evaluated at nine different doses, ranging from 16 Gy to 140 Gy. The minimal dose to approach full sterility was 100 Gy. Irradiation up to a maximum of 140 Gy apparently did not negatively impact the longevity of the adults. Even if both genders are sensitive to irradiation, the decline in fecundity for irradiated females could be exploited to release irradiated males safely to apply the SIT in combination with classical biological control. The data presented here allow us to consider, for the first time, the irradiation of bagrada adults as a suitable and feasible technique that could contribute to guaranteeing a safe approach to control this important pest species in agro-ecosystems. More research is warranted on the competitive fitness of irradiated males to better understand mating behavior as well as elucidate the possible mechanisms of sperm selection by polyandric B. hilaris females.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The stink bug, Bagrada hilaris, is a pest of mainly Brassicaceae crops. It is native to Africa and Asia and was recently reported as invasive in the southwestern part of the USA and in South America. ...There are no mitigation programs in place that do not involve pesticides. Therefore, much attention has recently been paid to the study of this species in order to identify sustainable and effective control strategies, such as the Sterile Insect Technique (SIT). In order to evaluate the suitability of the SIT on this pest, the mechanism of post-copulatory sperm competition was investigated. This is a polyandrous species, and it is thus important to understand whether irradiated males are able to compete with wild, e.g., non-irradiated, males for sperm competition after matings. Sperm competition was studied by sequentially mating a healthy virgin female first with a non-irradiated male, and then with a γ-irradiated (Co-60) one, and again in the opposite order. Males were irradiated at three different doses: 60, 80, and 100 Gy. The fecundity and fertility of the females, in the two orders of mating, were scored in order to perform an initial assessment of the success of sperm competition with a P2 index. Sperm from the non-irradiated male were utilized at the lowest irradiation doses (60 and 80 Gy), whereas the irradiated sperm were preferentially utilized at the highest dose (100 Gy). Bagrada hilaris exhibited high variability in P2 indexes, indicating a sperm-mixing mechanism.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Plant invasions are rarely homogenous. Processes such as selection, drift, gene flow, and founding events can rapidly shape the genetic diversity and spatial population structure of an invasion. We ...investigated the diversity, origins and population structure of
Verbascum thapsus
(common mullein), an introduced plant in North America. Despite this species being facultatively outcrossing, we found the invasion dominated by a single genotype (61% of plants were identical amplified fragment length polymorphism AFLP genotypes in the western USA). Fifty percent of the invasion populations were monotypic, and we found 32 genotypes overall in the 431 plants sampled from the invasion. In contrast, populations were much more diverse in the native Eurasian range, with 394 genotypes found in 479 plants. Further, we found an exact genetic match between the common genotype 1 in the USA and plants from Belgium and Germany. The identification of the most common and diverse invasive genotypes of common mullein allows their use in tests of management tools and further studies of mechanisms of this invasion.
French broom (Genista monspessulana) (Fabaceae) is a perennial species native to the Mediterranean basin. Introduced in the 19th century as an ornamental plant, it is currently invasive in California ...and Australia. The current research is focused on biocontrol with the use of the phytophagous weevil Lepidapion argentatum (Brentidae). Its capacity to develop both in the stem galls and pods of French broom makes it a promising candidate. The impact on the reproduction of French broom was studied in Southern France and revealed that it could effectively reduce the number of viable seeds by 18.8%, but also increased the number of aborted seeds by 10% within the attacked pods. To evaluate the specificity of L. argentatum, choice and no-choice tests were performed in 2012 and 2015 on a total of 36 non-target closely related species. Results revealed the presence of galls and larvae in the stems of seven species, including two endemic Californian lupines; i.e., Lupinus arboreus blue and Lupinus chamissonis. In the future, new tests will be conducted to determine if L. argentatum is able to complete its entire development lifecycle on the non-target species where galls have previously been observed.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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