Primary among these questions is: what fitness benefit does transmission into seeds provide to microbes and their host plants? Such a question gets at the eco-evolutionary dynamics in these microbial meta communities, which can have long-term consequences for both microbes and plants. Because microbial communities behave and evolve at shorter time-scales than macro-organisms , it is feasible to design simple experiments testing how microbes evolve in response to plant defenses, nutrient availability, and micromorphology. Such eco-evolutionary studies may have applications in understanding microbial community shifts with crop domestication . Additionally, both microbes and seeds have dormant stages, which can impact meta community dynamics through trade offs with dispersal and delayed responses to environmental conditions . The role of dormancy in seed and plant microbial meta community assembly has yet to be explored, so there is much room to study how dormancy impacts these systems over longer temporal scales. Finally, a hot topic in plant microbiome research is how to modify plant microbial communities for climate resilience and other beneficial traits . However, the impacts of climate change-associated disturbances on plant microbiomes have been limited to pattern-based studies in leaves and roots . As such, more work can be done on how disturbances alter seed microbiome assembly processes and outcomes.Classical biological control aims to control an invasive non-native species via the deliberate introduction of its specialized natural enemy. The use of classical biological control became popular after the dramatic success of the control program for cottony cushion scale, Icerya purchasi , a major citrus pest, through the introduction of the ladybird beetle, Rodolia cardinalis , to California from Australia in 1888 .

More recently, classical biological control continues to be used to suppress increasing numbers of invasive species worldwide. In the United States,dutch bucket for tomatoes it has been estimated that, while invasive insect species are only a small percentage of total arthropod species , they represent approximately 35% of 700 important insect pests . Thousands of classical biological control introductions have been made worldwide, and it has been estimated that, in 17% of cases, there has been effective control, to the extent that the targeted invader is no longer considered a pest. In 43% of cases, introductions have led to at least partial control, thereby reducing ecological damage and the need for pesticide use. However, 40% of introductions were found to have negligible impact on the target pest . Thus, though complete success is possible, it is not characteristic of most classical biological control programs. More commonly, it results in partial control which positively contributes to pest management. This method of biological control suppresses pest populations by releasing commercially produced natural enemies. This is particularly useful when natural enemies are not present or are scarce, such as in greenhouses or large monocultures. Within augmentative biological control, there are different methods for releasing insects. For instance, inoculative releases introduce small numbers of natural enemies, allowing them to establish in a crop, reproduce, and provide season-long control. Inundative releases, on the other hand, involve a mass introduction of natural enemies, with the expectation that they will provide an immediate reduction in pest densities. Yet the effect will be short lived, because they do not reproduce or establish . For example, mass releases of Trichogramma dendrolimihave proved to be effective for control of two major pests, Adoxophyes orana and Grapholitha molesta . When released in apple orchards, egg parasitism ranged from 81-99%. In this case, mass reared T. dendrolimi were labeled with a radioisotope to distinguish them from naturally occurring populations.

The released T. dendrolimi were responsible for 74% of the egg parasitism, while 26% of the parasitized eggs were attacked only by wild T. dendrolimi . This indicates that, not only was augmentation alone significant, but it may compliment scarce populations of natural enemies that are already present in the field. When cropping systems are altered to enhance populations of natural enemies, this is known as conservation biological control. In some cases, this can involve providing natural enemies with a suitable plant surface to forage on, as some crop cultivars can be incompatible with natural enemies. For instance, high densities of trichomes on tomatoes increased entanglement of lacewing larvae . Also waxy blooms on cabbage plants can reduce the ability of lacewing larvae to move effectively, reducing predation rates on the diamondback moth Plutella xylostella. Providing nutritional supplements, such as floral resources or food sprays, is another way to conserve populations of natural enemies. In New Zealand apple orchards, under-planting apple trees with floral resources increased parasitism rates of Epiphyas postvittana. In cotton, reproduction of lacewings was enhanced by spraying a mixture of hydrolyzed protein, water, and sugar . While adding food sources and suitable habitat can enhance natural enemies, it is equally important to alter management practices that decrease natural enemies, namely, pesticides. Soon after the introduction of synthetic insecticides in the 1950s, researchers began to link secondary pest outbreaks and pest resurgence to the destruction of natural enemies . Since, then it has become abundantly clear that pesticides can affect natural enemies in numerous ways, inducing changes in foraging behavior, predation rates, survivor ship, fertility, fecundity, and development rates .Ladybird beetles, or coccinellids, are important predators of many pest species, including whiteflies, aphids, mealybugs, scales, and mites. In particular, aphidophagous ladybird beetles are prominent generalist predators . As mentioned above, one of the most well-known examples of the use of coccinellids in classical biological control was the importation of the vedalia beetle, Rodolia cardinalis , to control the cottony-cushion scale on citrus in California. Immediately after this success, many classical biological control programs began to focus on Coccinellidae, leading to the “ladybird fantasy” period .

One coccinellid commonly used in biological control programs in the United States is the generalist predator Hippodamia convergens. It is frequently used in augmentative biological control because it is easily collected and stored. In California, they are collected from overwintering sites in the Sierra Nevada and sold commercially, yet still maintain their ability to prey on pests relative those not collected and stored for commercial use . Due to rapid dispersal in a field setting, it is thought that mass releases of commercial H. convergens is ineffective . For instance, for aphid control in roses, the effective rate of H. convergens release was two orders of magnitude greater than recommended by commercial insectaries, and was no more cost effective than an application of the systemic pesticide imidacloprid . On the other hand, when placed in a more contained environment, such as a greenhouse, H. convergens has the ability to reduce pest populations . Additionally, H. convergens may be incorporated into conservation biological control programs. In western North America, it is an important natural enemy in high-value tree crops . However, some reduced-risk pesticides used within this system have been found to be toxic to H. convergens . Understanding how pesticides impact populations of natural enemies is key to integrated pest management and the conservation of natural enemies. For decades, the use of organophosphate pesticides has disrupted the activity of natural enemies. With the passage of the Food Quality Protection Act in the United States in 1996, this class of conventional pesticides became the primary focus of a registration review. With increased restrictions on use of organophosphates, growers began to use alternative pesticides for the control of pest populations. From 1990 to 2007, the use of organophosphates declined by approximately 60%, from 85 million pounds to 33 million pounds, and decreased from 70% of total insecticide use to 36% . In 1992, via the Federal Register, the Environmental Protection Agency Office of Pesticide Programs called for incentives to promote development and use of reduced-risk pesticides. The following year,blueberry grow pot the same office announced the Reduced-Risk Pesticide Initiative. The goal of this program was to promote the development and use of pesticide products that would pose a reduced risk to human and environmental health. Additionally, the EPA created incentives to promote registration of these pesticides under the new reduced-risk criteria. These criteria included reducing human health risks by reducing toxicity by a factor of 10-100 times relative to organophosphate insecticides. Of particular concern was reducing health hazards to pesticide applicators and field laborers, which is another reason the EPA actively promoted the replacement of organophosphates. In addition to human health, the criteria specified a reduction in risk to non-target organisms such as birds, beneficial insects, and aquatic organisms . Though the Reduced-Risk Initiative criteria aimed to reduce risks to human and environmental health, reduced risk does not guarantee there are no harmful effects to other non-target organisms, such as natural enemies. Chlorantraniliprole belongs to a class of chemicals known as anthranilic diamides. It acts on insect ryanodine receptors, and is most effective when applied to plant material and ingested. One formulation of this chemical is Rynaxypyr, the active ingredient in the pesticide Altacor. Altacor is designed to target various lepidopteran pests, such as leafrollers, crown borers, leafminers, and codling moth. It is approved for use in fruiting shrubs, vines, and tree crops, including banana, citrus, and pome fruit . Thus far, chlorantraniliprole appears to have little to no toxicity for most natural enemies. For example, it has shown demonstrated to have no toxic effects on the dogbane beetle Chrysochus auratus, , a beneficial insect that feeds almost exclusively on problematic weeds in blueberry crops .

According to the IOBC toxicity classification, chlorantraniliprole was ranked as slightly harmful to Orius armatus , which controls western flower thrips in greenhouse grown peppers . Similarly, it was found to be compatible with beneficial insects such as the Bombus impatiens , Copidosoma bakeri , an endoparasitoid, the predatory ground beetle Harpalus pennsylvanicus , and the ectoparasitoid, Tiphia vernalis. When tested for behavioral effects on the generalist predator Macrolophus pygmaeus , exposure to chlorantraniliprole reduced feeding, but had no significant effect on predation rates . Furthermore, there were no significant effects on survival, parasitism rates, or emergence of seven different species of parasitic wasps, including two sensitive indicator species, Aphidius rhopalosiphiand T. dendrolimi . When treated with chlorantraniliprole, adult and immature Deraeocoris brevissurvived at rates comparable to controls . Yet, contrary to the aforementioned studies, chlorantraniliprole caused 100% mortality in two species of green lacewing, Chrysoperla carnea and Chrysoperla johnsoni. Cyantraniliprole is also an anthranilic diamide. Another version of this active ingredient is known as Cyazypyr. Under the trade name Exirel, it is approved for use in several crops, including bushberries, citrus, pome, stone fruit, and tree nuts. With respect to high value tree crops in western North America, it is approved for use in Washington and Oregon, but not in California. This pesticide targets chewing and piercing sucking insects, primarily from the orders Lepidoptera and Hemiptera. Both Altacor and Exirel pose little human health risk. However, unlike Altacor, Exirel has application restrictions due to its risk to insect pollinators . Cyantraniliprole has been demonstrated to have no significant impact on the mortality of Tamarixia triozaewhen it is exposed to residue on either a glass or leaf surface . However, 25% of T. triozae died 24 h after ingestion of treated honey. For the predator mite, Galendromus occidentalis , cyantraniliprole caused no significant changes in mortality, egg hatch, or larval survivor ship, but there were reductions in prey consumption and fecundity . The treated larvae of two lacewing species, C. carnea and C. johnsoni, did not experience significant mortality or differences in sex ratio, yet exposure was highly toxic to adults . In nymphs of the predatory mirid, D. brevis, 23% mortality was observed when treated with the maximum recommended field rate, but there was no significant impact on mortality for treated adults . Additionally, treated nymphs had no significant difference in development time, but, when they emerged as adults, the sex ratio had a significant female bias . When applied as a systemic treatment in peppers , cyantraniliprole was found to have no impact on Orius insidiosuspopulations, but it also had no impact on populations of the target pest . Copper hydroxide and mancozeb are two active ingredients that may be mixed in a single pesticide solution and applied as a spray to control plant pathogens.