CSIRO European Laboratory: Weed warriors, pest planners, and dung diplomacy − benefits of 60 years of native range research for effective biological control agents to Australia

The current status of biological control of weeds in southern China and future options

Indirect nontarget effects of host-specific biological control agents: Implications for biological control

The alder leaf beetle (Agelastica alni L., Coleoptera: Chrysomelidae) causes approximately 10% of total economic damage to hazelnut product per year in Turkey. A. alni larvae are susceptible to several pathogens indigenous to the area in which these insects occur in Turkey. In the present study, in order to find a more effective and safer biological control agent against this common pest, we evaluated the various biological agents’ insecticidal activity during the four hazelnut seasons from 2002 to 2005 on the larvae of the alder leaf beetle collected from the vicinity of Trabzon, Turkey. The tested agents are 25 insect-originating bacteria, 2 bacterial toxins and 1 viral preparation. The results showed that the highest insecticidal activity was obtained by bacterial isolates at 1.8 × 109 bacteria/mL dose, within ten days on the larvae of A. alni. These are 90% for Bacillus thuringiensis biovar tenebrionis (4AA1), Bacillus sphaericus (Ar4, isolated from Anoplus roboris L., Col.: Curculionidae), and Bacillus thuringiensis (Mm2, isolated from Melolontha melolontha L., Col.: Scarabaeidae). Our results indicate that these isolates may be valuable as biological control agent.

Because many invasive plants are anticipated to benefit from climate change, the need for effective management strategies will become more pressing in the future. Biological control of invasive plants by insects has been an effective management strategy in many instances, but climate change may substantially alter such systems. Maximizing biological control efficacy with climate change will require predicting responses of the invasive plant in question, its biological control agents, and especially their corresponding interactions. However, because of the wide variety of species-specific plant and insect responses to increased atmospheric CO 2 concentrations, temperatures, extreme weather events, and other climate factors, climate change will likely result in highly variable, system- and geographically-specific effects. Even still, predicted future climates are generally anticipated across systems to alter geographic ranges of invasive plants (and correspondingly their biological agents), reduce host-plant quality, and hasten the phenology of both plants and insects. Some of these anticipated effects on biological control systems can be expected to hamper control efficacy. However, because some of these effects might also increase control efficacy, biological control can still be an effective and important management tool in the face of climate change. Although the variety of insect and plant responses to climate change reported in the literature do not currently allow for strong generalizations to be made as to the best biological control agents or strategies in novel climates, pertinent considerations for selecting effective biological control agents in the future are discussed.

Biological control agents against the cabbage stem flea beetle in oilseed rape crops

Effective biological control of chickpea rabies (Ascochyta rabiei) through systemic phytochemical defenses activation by Trichoderma roots colonization: From strain characterization to seed coating

Predaceous insects is an effective important biological control agents of feeding on Tetranychus urticae Koch and decreasing the number during 2018 season to study the optimal predator: prey ratios for the release of Stethours gilvifrons (Mulsant) sacond larvae and adult stage for controlling the T. urticae on cottonplants Gossypium burbadense L. The obtained results showed that the effective control was gained after 12 days from released the second larvae and adult of the S. gilvifrons predatorwhen the predator: prey ratios were 1:15and1:25 respectively. The regression analysis between predator: prey ratios of S. gilvifrons (larvae and adults) reduction percentages cleared that there were negatively high relationship of larvae and adult predators and prey ratios, which means that the reduction rate was increased with lower predator : prey ratios and vice versa .The results assured that the best control of T.urticae populations under semi field conditions was cleared by using the lower predator prey ratios (1:15 and 1:25) . Finally the predators can be used as biological control agents for T.urticae in cotten plantation under field conditions. The regression analysis between P: p ratios of S. gilvifrons adults and reduction percentage of the T.urticae mites , data showed there were negatively highly relationship of both predators larvae and adult which means that the reduction rate was increased with lower P: p ratios and vice versa.

Interactions of a Nucleopolyhedrovirus with Azadirachtin and Imidacloprid

Diadegma semiclausum is one of the promising biological control agents used to control the pest of cruciferous crops, Plutella xylostella. Its mechanism of action is by injecting its egg into the second and third instar larva of P. xylostella. The egg will develop inside the larva, causing the larva to weaken and reducing the population of P. xylostella in the field. This tiny parasitoid was introduced from Australia in the late 1970’s and has since been utilized as a biological control agent in cruciferous vegetable farms across the Cameron Highlands. As a key component of Integrated Pest Management (IPM), the use of biological control agents promotes the reduction of synthetic pesticide applications, aligning with sustainable agricultural practices. In 2019, MARDI reintroduced D. semiclausum to the Cameron Highlands, where the parasitoids were mass-reared at the insect rearing laboratory and subsequently released into selected vegetable farms to evaluate their effectiveness and field population stability. Six farmers representing different zones; Habu and Batu 33 (southern zone), Sg. Palas and Sg. Menson (central zone), and Ulu Telom and Kg. Raja (northern zone) was selected for scheduled D. semiclausum releases. Each farm was visited three times within three months. During each visit, both D. semiclausum and P. xylostella populations were monitored, and pupa samples were collected for laboratory assessment of parasitism rates. Additionally, 100 to 200 adults of D. semiclausum were released per visit at each farm. Throughout the program, farmers received training to identify biological control agents and other beneficial insects, along with guidance on safe pesticide usage and the adoption of environmentally friendly alternatives. Field observations demonstrated a consistent increase in D. semiclausum populations, accompanied by a corresponding decline in P. xylostella populations over the three visits, indicating the parasitoid’s potential as an effective biological control agent. Laboratory assessments recorded an average D. semiclausum parasitism rate of 83.33%, whereas field parasitism rates ranged from 43% to 73.33%. The comparatively lower field parasitism rates suggest that D. semiclausum populations were still establishing stability under field conditions. From the economic study, the biological control was costing RM57,491/ha with a net profit of RM32,989/ha and a Benefit-Cost Ratio (BCR) of 1.57. In contrast, conventional farming had lower costs (RM53,603/ha), higher profit (RM40,897/ha), and a better BCR of 1.76. While conventional methods currently yield better returns, long-term pesticide use may lead to insect resistance and rising costs. Thus, biological control offers a safer and more sustainable alternative for the long-term effects.

The status of weed biological control in the six Greater Mekong Subregion (GMS) countries was assessed, and opportunities to develop biological control in the region are proposed. Twenty biological control agents targeting nine weed species have been introduced into GMS countries, with 13 agents establishing on seven weed species. Another nine biological control agents have spread unintentionally into the region. These agents are having a slight to high impact on their target weeds. However, the number of weeds in the region that have been targeted for biological control is only a fraction of the number of weeds (45) in the region that have been targeted for biological control elsewhere. This presents a tremendous opportunity to expand weed biological control in the region and reduce the dependency on herbicides while increasing productivity. There are numerous highly effective biological control agents present elsewhere that could be introduced to assist with the management of the region's most important weeds, such as Pistia stratiotes , Salvinia molesta , Chromolaena odorata and Mikania micrantha . Along with the introduction of biological control agents, there is also a scope to increase the capacity and training in biological control within GMS countries to develop effective weed control and management.

There is a strong focus in this issue on biological control agents; how they are regulated across the EPPO region, how their use can be facilitated, and how they may contribute to slowing the spread of invasive pests and mitigating the damage they cause. A workshop on this subject was held in Budapest last November. It highlighted the considerable variation in practice across the region in the regulatory processes around decisions to release biological control agents. Conclusions from the workshop and recommendations for further steps towards harmonisation and collaboration are presented here. The specific arrangements in France and Hungary are described, as is EPPO's guidance to members on biological control agents. It was helpful for the workshop to hear about the recent experience of the European Food Safety Authority when developing an opinion on the proposed release of a non-indigenous biological control agent against an invasive species of acacia in Portugal. That experience has also been written up for this issue. We have included three articles on Dryocosmus kuriphilus; a pest of chestnut which appears to be spreading in Europe, but against which an effective biological control agent is available. A survey of parasitoids of Cydia pomonella in Syria continues the biological control theme. There are a number of papers on Hemiptera, with reports of scale insects and mealybugs from around the Mediterranean and a list of interceptions from the Republic of Korea. Spread and damage caused in Italy by Halyomorpha halys (particularly on pear) and by thousand cankers disease on walnut are both described. An argument is made for focusing action against pests while they are still of limited distribution, drawing on the example of invasive plants in Israel. Finally this issue reports results and recommendations from two recent studies; the EU Q-collect project on collections of importance to plant health and an EPPO study on the different categories of processed wood material being traded into and within the region. Thank you, as ever, to all contributors who have provided papers and to those who participated in the workshops and projects to which they refer.

Plant evolutionary ecology: molecular genetics, global warming and invasions, and the novel approaches we are using to study adaptations

Epicoccum species are ubiquitous ascomycetes. Several species are known to cause plant diseases and some species act as biological control agents against a range of plant pathogens. Accurate identification of Epicoccum species is paramount to a successful disease management program and successful development of biological control products. There are 18 Epicoccum species that are associated with diseases of 46 plant species. The diseases occur in 20 countries with leaf spot as the most commonly reported disease symptom. There are a further five Epicoccum species (E. nigrum, E. layuense, E. dendrobii, E, mezzettii and E. minitans) that have biological control activity against various plant pathogens. Of the five species, Epicoccum nigrum is the most promising and has been shown to reduce incidence and severity of a wide range of plant diseases. The use of bioactive metabolites (e.g. flavipin and epicolactone) from Epicoccum spp. may offer growers a cheap and safe alternative to conventional pesticides which are widely used to manage plant diseases. We review the current knowledge of Epicoccum species, both those species that are plant pathogens, and those species that are biological control agents for plant disease.

Analysis of Trichoderma as an effective biological control agent against the honey fungus (Armillaria spp.)

The biological control of disease vectors