Integrated Pest Management in Tree Fruit Crops

J.F. Brunner , in Encyclopedia of Agriculture and Food Systems, 2014

Chemical Control

Chemical controls (pesticides) are often the dominant tactic used in IPM programs. Chemical controls are designed to reduce pest (insect, pathogen, rodent, etc.) populations below levels that will not negatively impact the crop. Before the development of synthetic insecticides, which occurred after World War II, pesticides included horticultural oils, lead arsenate, soaps, lime sulfur, nicotine, and a few other inorganic elements like sulfur and copper. The modern pesticide era began with the discovery of chemicals like dichlorodiphenyltrichloroethylene and organophosphate (OP) insecticides that had high efficacy against insects. Their dramatic effect against pests of agriculture resulted in their overuse leading to a crisis that eventually resulted in an alternative approach, the development of IPM. IPM viewed chemical controls as one tool integrated into an overall strategy to mitigate the negative impacts of pests on a crop. Because of the high and often immediate impact of chemical controls on a pest population, their appropriate place in an IPM program was as a last resort in a multitactic approach.

The regulation of pesticides through the US Environmental Protection Agency (EPA) has changed the availability of chemical controls over the past two decades. The US federal Food Quality Protection Act (FQPA) of 1996 required the EPA to review and reregister all pesticides on the basis of risk. In addition, all uses of a pesticide were considered in determining risk, not just agricultural uses. This represented a significant shift from the previous regulatory approach, which balanced risks and benefits of pesticides. The highest priority for the reregistration of pesticides under FQPA was the OP insecticide class. Specialty crops were one of the biggest users of this insecticide class, so they were especially impacted by FQPA. Progress of EPA toward the implementation of FQPA can be found on their web site.

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Water hyacinth: review of its impacts on hydrology and ecosystem services—Lessons for management of Lake Tana

Minychl G. Dersseh , ... Dessalegn C. Dagnew , in Extreme Hydrology and Climate Variability, 2019

19.6.3 Chemical methods

Chemical control is a practice that can be done by applying herbicides directly on the leaves of water hyacinth. The first chemicals which have been used to control water hyacinth in the United States were inorganic chemicals such as ammonia, sodium chloride, barium chloride, and sulfuric acid ( Bose, 1945; Penfound and Minyard, 1947). One of the herbicides, glyphosate, is the most suitable and safe for application, the cost of application is estimated at US$28/ha. Another herbicide which is safe for fish is 2, 4-D. This is because of its rapid degradability in the environment and it is cheaper than glyphosate. The herbicide 2, 4-T that is forbidden to use as herbicide, could be mistaken for 2, 4-D (Charudattan et al., 1995).

In the United States, 2, 4-D, diquat and glyphosate have been used since the 1946, 1956, and 1978 respectively (Center, 1996). The relative comparison of the cost of these chemicals is that glyphosate is more expensive than 2, 4-D. If we use these chemicals according to their instructions, there will be minimal adverse effects on the environment and human health. All have water, fish, and shellfish tolerance property. All these chemicals have short lives in water (Joyce and Ramey, 1986). Plants which have been sprayed by these herbicides twist their leaves within 24   h and begin sinking in a few weeks (Penfound and Minyard, 1947). Besides the conventional herbicides, other inorganic chemicals such as Ca(OH)2 (lime), CaCO4 (limestone), and CaSO4 (gypsum), Fe-CaSO4 (iron gypsum), and Al2(SO4)3 (alum) are used in reducing the fast growth of aquatic plants in hard water eutrophic lakes. The action of these chemicals in reducing the plant growth is by binding phosphorous and precipitating it out of the water into sediments (Quiroz et al., 1997; Salonen et al., 2001).

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African perspective of chemical usage in agriculture and horticulture—their impact on human health and environment

Aliyu Ahmad Warra , Majeti Narasimha Vara Prasad , in Agrochemicals Detection, Treatment and Remediation, 2020

16.2.7 Safer low-cost alternatives to agrochemicals for agricultural sustainability in Africa

Chemical control has highly expanded over the last 30 years in SSA to reduce bioaggressors on all crops. Pest management of fruits and vegetables by small farmers in SSA has developed anarchically in a fuzzy regulation framework. Due to criticism of pesticide toxicity and excessive application by both farmers and consumers, pesticide management in SSA over the past 30 years was reviewed. Alternatives to improvement and reduction of pesticide application, in order to decrease environmental and human hazards, were proposed The major points were highlighted as follows: (1) global changes in SSA such as urbanization modify farmer practices and crop losses. (2) Pesticides are more and more used by small farmers in an unsustainable way. (3) The risk of pesticide application for human health and environment is poorly known. (4) Options to reduce pesticide application based upon IPM and agroecology. IPM is an approach that does not rule out the use of pesticides but uses them as little as possible and only for strong reasons. It promotes the use of safer alternatives, such as biocontrol, which uses natural enemies to control pests, and cultural control practices that modify the growing environment to reduce unwanted pests. These approaches include the following: (1) the use plant varieties that have been bred to resist insect damage (resistant cultivars). (2) Practice of crop rotation that changes the crops planted every season, or year, to break the life cycle of insect pests and discourage pests from staying on the farm. (3) Techniques of habitat manipulation, which involve planting a variety of crops in and around the farm in order to increase the number of natural insect enemies on the agricultural farm land. (4) The use of small glue (pheromone traps) that contains insect pest attractants. Integrated approaches to pest management appear to hold more promise than single approaches. The challenge is to ensure that African farmers adopt practices that are sustainable and friendly to the environment and human health (Ngumbi, 2018). Increasing farmer's awareness and training aimed at sustainable agriculture and IPM was also suggested by Nonga et al. (2011). To be more elaborate some positive alternative methods have been already developed such as physical barriers, cropping practices, genetic improvements, semiochemical use, and biological control options with beneficial insects and mycopesticides (Hubert de Bon et al., 2014).

Effort was made for considering indigenous resources such as pesticidal plants and insect natural enemies in the wider context of natural capital that provide valuable ecosystem services (including pest control), which will facilitate greater recognition of their true economic and societal worth. Both of these model systems show promise; however, there are significant challenges to be overcome in developing production, supply, and marketing systems that are economically viable and sustainable. The regulatory environment must also evolve to accommodate and facilitate the registration of new products harvested and the establishment of appropriate supply chains that share the benefits of these resources equitably with the local communities (Grzywacz et al., 2014).

Natural farming as an alternative to agrochemical usage in the context of its eco-friendly nature and sustainability minimizes the external inputs to the farm land and nurtures the soil fertility which in contrast to conventional chemical farming practice that employs the indiscriminate use of chemical fertilizers and pesticides to destroy the beneficial soil microflora, change the soil nature, and also contribute to the high crop production cost (Deviant, 2016).

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Living with Harmful Algal Blooms in a Changing World

Clarissa R. Anderson , ... Caroline K. Cusack , in Coastal and Marine Hazards, Risks, and Disasters, 2015

17.3.1 Biological and Chemical Control Methods

Biological and chemical controls refer to direct application or stimulation/suppression of factors that modify the biological (e.g., growth, grazing, mortality) or chemical (e.g., pH, inhibitors) composition or function of the ecosystem. These controls are often administered as emergency measures for suppressing blooms that threaten aquaculture facilities, or other spatially restricted regions, and their use can significantly accelerate the demise of a bloom or rid the water of toxins. These methods are most successful over small spatial scales within confined fish farms, reservoirs, desalination plants, or lakes and involve the manipulation of the environment and/or causative organism (Anderson et al., 2001; Kim, 2006). Biological agents such as grazers, parasites (Kim et al., 2008; Mazzillo et al., 2011), viruses (Nagasaki et al., 1999), and algicides (e.g., Jeong et al., 2003; Kim et al., 2009) are often host specific (Kodama et al., 2006) targeting a particular HAB species. Other moieties such as clays are used to promote flocculation and settling of algal particles to the sediment. Everything from microbial biosurfactants called sophorolipids (Sun et al., 2004; Lee et al., 2008) to algicidal bacteria (Imai et al., 1998; Doucette et al., 1999; Gumbo et al., 2008; Kang et al., 2008; Roth et al., 2008; Kim et al., 2009) and fungi (Jia et al., 2010) can be effective, at least in laboratory settings. The most extensively studied biocontrols target the PSP-producing Alexandrium spp. (Nakashima et al., 2006; Amaro et al., 2005; Bai et al., 2011; Su et al., 2007, 2011; Wang et al., 2010, 2012) or the fish-killing Cocholidinium spp. (Jeong et al., 2003; Kudela and Gobler, 2012), Heterosigma akashiwo (Nagasaki and Yamaguchi, 1997; Lovejoy et al., 1998; Imai et al., 1998; Jin and Dong, 2003; Kim, 2006), and Chatonella spp. (Imai et al., 2001). Zhou et al. (2008) achieved 80 percent inhibition of several species of Alexandrium in culture after applying garlic extract above 0.04 percent and attributed this effect to the active ingredient, diallyl trisulfide. This sort of "environment–friendly" approach to bloom control is appealing given the uncertainty and risk surrounding the use of toxic chemical agents that endanger a variety of aquatic flora and fauna. These compounds also minimize the issues associated with more environmentally damaging mitigation methods such as the use of copper sulfate (CuSO4) on K. brevis blooms in the 1950s (Rounsefell and Evans, 1958 as cited in Kim, 2006). However, CuSO4 and chlorination are still used routinely to rid drinking water reservoirs of nuisance algae and toxins (McKnight et al., 1983; Zamyadi et al., 2012).

Clay minerals such as kaolinite and loess compounds have been used effectively to control blooms in Asia, Europe, and the United States. Suspensions of the clay are sprayed onto the surface layer of a bloom (Figure 17.6), resulting in scavenging and flocculation of algal cells with over 80 percent removal efficiency from surface waters in some cases (Sengco and Anderson, 2004). Phoslock® (lanthanum-modified bentonite) and chitosan have been applied to cyanobacterial blooms but prove too costly and impractical for routine management in the United States (Sellner et al., 2013), and in the case of Phoslock®, can lead to phosphorous limitation and increased ammonium regeneration (Sellner et al., 2013), further promoting cyanobacteria that respond to both P and N inputs (Paerl et al., 2011). Bloom removal is often successful only at very high clay and chitosan concentrations, with HAB species, pH (i.e., time of day), growth phase, and chitosan quality influencing results (Sellner et al., 2013). In lakes and ponds, barley straw and its extract can be cost-effective alternatives to controlling toxic cyanobacterial blooms and subsequent regrowth (Sellner et al., 2013; references in Brownlee et al., 2003), but it may have limited use in coastal marine environments where only a few dinoflagellate species appear susceptible (Terlizzi et al., 2002; Brownlee et al., 2003; Hagstrom et al., 2010). Peroxide additions are also effective (e.g.,Matthijs et al., 2012) but limited due to cost and hazardous chemical permitting (particularly in the United States). In addition, little is known about the effects that this removal of toxic phytoplankton to the benthos has on the biota (Shumway et al., 2003) or on the potential for anoxic conditions in deeper waters (Imai et al., 2006). The list of physical disturbance methods now being tested is long, and most do not translate well to open coastal zones despite success in lakes and fjords; these include sediment capping (Pan et al., 2012), dredging (Lurling and Faassen, 2012), and even solar-powered circulation (Hudnell et al., 2010). A novel and potentially environmentally benign approach to control of blooms of cyst-forming HAB species (e.g., Alexandrium) in shallow, localized systems is being explored wherein manual mixing of bottom sediments can bury cysts uniformly throughout the disturbed layer, greatly reducing the number of cysts in the oxygenated surface layer, and thus the potential inoculum for future blooms (D. Anderson and D. Kulis, pers. comm.).

Figure 17.6. Southern Sea of Korea. Clay dispersal used to mitigate blooms of Cochlodinium polykrikoides.

 Photos by S. Moore.

Viral and bacterial lysis appear to play a natural role in regulating phytoplankton communities and carbon flux (e.g., Fuhrman and Azam, 1980; Salomon and Imai, 2006). Capitalizing on this natural pathogenicity seems like a logical, cost-effective solution to HAB control. However, society has grown weary of runaway experiments with nature that introduce foreign, potentially invasive species or irreversibly alter natural assemblages in an ecosystem (Sanders et al., 2003; Secord, 2003). Given how poorly we understand phytoplankton community ecology, let alone viral and bacterial systematics and ecological interactions, Secord (2003) warns of the possibility for evolving host specificity in introduced viral and bacterial biocontrols that may not only prey switch but also could become less effective as their HAB hosts start to develop resistance. In a thought-provoking review on algicidal bacteria, Mayali and Azam (2004) considered the broader ecological context of microbial interactions in phytoplankton communities. Despite the many laboratory studies demonstrating the harmful predatory effects of heterotrophic bacteria on algal species, they argued that most field studies have failed to show conclusively the causal relationship between the decline of a bloom in natural ecosystems and the behavior of an introduced, algicidal bacterium. Moreover, translation from laboratory conditions to the field is inherently complex, given the flexibility of predator–prey dynamics mediated by the presence or absence of other algal species (Mayali and Azam, 2004) and the potential for toxicity effects due to HAB–microbe interactions (Moore et al., 2008).

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The Oceans and Marine Geochemistry

F.J. Millero , in Treatise on Geochemistry (Second Edition), 2014

Abstract

The physical–chemical controls on seawater can be attributed to the effect that the composition of the major components have on the thermodynamics and kinetics of processes in the oceans. In this chapter, an earlier review on the experimental and modeling work that has been done on how the major components of seawater control rates and equilibria of processes in the oceans has been updated. The effect of major components on the physical–chemical properties of seawater, the carbonate system in the oceans and the effect of ocean acidification on speciation of metals in seawater has been emphasized.

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Advanced Modelling Techniques Studying Global Changes in Environmental Sciences

Wei He , ... Xiang-Zhen Kong , in Developments in Environmental Modelling, 2015

8.2.2.2 PCCs' screening

Many ranking methods for PCCs are based on scoring (Sampaolo and Binetti, 1986; Timmer et al., 1988; Zitko, 1990; Swanson et al., 1997; Snyder et al., 2000). A few employed risk assessment to rank the PCCs (Hansen et al., 1999). In this paper, eco-risk at mid-level calculated by BMC and RQ (EEC/PNEC ratio) were used to rank the PTSs in BTB area. Eco-risk value >   0.1, 0.001–0.1, 0.001–10−   6, and 10–6 indicated that PTSs posed a very high, high, potential, and litter risk to the aquatic ecosystem. RQ value >   1 and <   1 indicated that PTSs posed high and low risk to the aquatic ecosystem. After ranking the eco-risk and RQ from high to low, the top 25% of the sequences was screened as the criterion for PCCs.

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Introduction and historical perspective

Terry J. Gentry , David A. Zuberer , in Principles and Applications of Soil Microbiology (Third Edition), 2021

Biological control

Compared to the chemical control of pests, the advantages of biological control are numerous. Biological control is a natural mechanism that does not employ pesticides and therefore leaves no xenobiotic residues after treatment ( Chapters 21 and 23 21 23 ). Early attempts at biological control using soil microbes followed Waksman's discovery of antibiotic-producing microbes in the soil. Unfortunately, most if not all of those attempts failed outright.

Since that time, soil microbiologists have learned that it is not sufficient to just increase the number of biological control agents in the soil to achieve success; a basic understanding of the ecology of the biological control agent is also needed. Amelioration of the factor(s) limiting the growth or survival of the control agents is necessary for biological control to work. While successful biological control experiments are few in number in comparison to failures, biocontrol research continues to be an area where soil microbiologists make significant contributions. As we learn more about biological control agents and their pest-suppression mechanisms, ecology, and genetics, this area of soil microbiology research should continue to increase in importance, especially with increasing interest in organic agriculture and restrictions on chemical pesticides.

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Trace Fossils as Indicators of Sedimentary Environments

Nicola S. Tonkin , in Developments in Sedimentology, 2012

6 Conclusions

The dominant physico-chemical controls in ancient river deltas are the sedimentation rate and the salinity; these parameters control the spatial distribution of trace fossils. Bioturbated fluvial-dominated and tidal-dominated ancient deltaic successions contain mostly of trace fossils made by euryhaline organisms, while wave-dominated deltaic successions contain a mix of both euryhaline and stenohaline organisms. Deltaic successions are typically stressed or mixed expressions of Skolithos and Cruziana ichnofacies, with Cruziana elements becoming more distinct in the distal delta front to prodelta. The dynamic combination of fluvial, tidal, and wave processes creates distinct environments and subenvironments with corresponding ichnological signatures (see Fig. 1 and Supplementary Table 1: http://booksite.elsevier.com/9780444538130).

Fluvial-dominated deltas have a weaker ichnological marine signature in the lower delta plain and proximal delta-front environments than their marine and tidal counterparts. Fresh- and brackish-water trace-fossil assemblages with absent to high BI and reduced diversity (BI   =   0–4; Supplementary Table 1: http://booksite.elsevier.com/9780444538130) dominate in proximal settings. The ichnodiversity and BI of assemblages increase markedly (BI   =   3–6; Supplementary Table 1: http://booksite.elsevier.com/9780444538130) seaward of fluvial influence in the marine distal portions of the fluvial delta complex (Fig. 3A).

In tide-dominated deltaic successions, the marine ichnological signature extends into the lower delta plain as a result of the salinity wedge (Fig. 3B). High-diversity trace-fossil assemblages of brackish to marine trace fossils persist throughout the successions, while the BI is high but variable (BI   =   0–6; Supplementary Table 1: http://booksite.elsevier.com/9780444538130).

In wave-dominated deltas, the marine signature is also suppressed in the lower delta plain, with absent to moderate BI (BI   =   0–3; Supplementary Table 1: http://booksite.elsevier.com/9780444538130). In the strongly marine, high-diversity and intensity assemblages (BI   =   0–5; Supplementary Table 1: http://booksite.elsevier.com/9780444538130) of the delta front and prodelta, it is often difficult to distinguish non-deltaic shoreface from offshore successions (Fig. 3C), unless three-dimensional data are available.

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Agricultural and Related Biotechnologies

Peter G. Kevan , Les Shipp , in Comprehensive Biotechnology (Third Edition), 2019

4.66.1 Introduction

Pest management is important to agriculture and forestry. Chemical control measures against pests became standard after the invention and proof of efficacy of chemical pesticides. However, other approaches have proven valuable. Biological control is simply the use of biological agents in pest management for the production of food and fiber for human consumption. Many ecologists argue that biological control is, and always has been, nature's way of regulating populations. The idea that organisms can be pests is an anthropocentric construct whereby the pest is an organism that detracts from the production of resources that human beings want. Pests come in various guises. Predators are pest of livestock, herbivores are pests of crops, parasites and pathogens are pests of livestock or crops, and competitors may become so numerous as to detract from plant or animal production.

Biological control agents are simply living organisms (or parts of living organisms) that interfere with the productivity of other living organisms. In terms of biotechnology, biological control agents are used by human beings for the protection of the resources that they want. Just as pests run the gamut from vertebrates to virus, so do biocontrol agents.

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Periphyton Functions in Adjusting P Sinks in Sediments

Yonghong Wu , in Periphyton, 2017

6.4.2 The Influence of Periphytic Biofilm on Sediment P

Previous studies have already indicated that periphytic biofilm can control chemical fluxes of calcium, alkalinity, and P from the sediment to the overlying water (Woodruff et al., 1999a,b). Some studies have also indicated that the presence of periphytic biofilm in the sediment–water interface could reduce the release of sediment P to overlying water (Wu et al., 2010b; Zhang et al., 2013a). Our experiments showed similar results. For example, the sediment under control conditions was a P source that released P, especially Labile-P and Fe/Al-P, into the overlying water. In the presence of periphytic biofilm, the sediment could be a short-term P sink that accumulated P (like Fe/Al-P and Ca-P) in the initial 7   days. After 7   days, all types of P fractions in the sediment were released into the water column, but generally less was released by sediment with periphytic biofilm. This further indicated that periphytic biofilm could reduce the release of sediment P to overlying waters.

It was interesting to find that more Fe/Al-P of sediment was released in the presence of periphytic biofilm than in the control after 30   days. This implied that periphytic biofilm could release more Fe/Al-P over a relatively long time. One possible explanation is that the long-term presence of periphytic biofilm between water and sediment may induce a rise in sediment pH, favoring the release of Fe/Al-P from sediment (Jin et al., 2006a,b; Rydin, 2000). As a result, more Fe/Al-P was released from the sediment to the overlying water in the presence of periphytic biofilm than in the control after 30   days.

The release of P from surface sediments is an important process for understanding aquatic P cycling. In sediment, only some P fractions are easily exchangeable and biologically available, while most of them (about 8–82%) bind with cations like Ca, Fe, and Al (Renjith et al., 2011; Rzepecki, 2010). It is well known that Labile-P, extracted with NH4Cl, often represents pore water-P, loosely sorbed P, and CaCO3-associated P in hard waters, while Fe/Al-P, extracted with NaOH-P, is a type of P exchangeable with OH−, mainly aluminum and ferric. Ca-P, extracted with HCl, is a P form sensitive to low pH, assumed to consist mainly of apatite, and Residual-P consists mainly of refractory organic P as well as the inert inorganic P fraction (Rydin, 2000). In our experiment, the presence of periphytic biofilm generally decreased the release of Labile-P, Fe/Al-P, and Ca-P, and did not alter the trend of sediment P in 60   days. Among the various P fractions, it is worth noting the change of Ca-P in sediment. Ca-P is thermodynamically regarded as a more stable mineral-bound form than Fe/Al-P (Ann et al., 1999). Normally, Ca-P accounts for about 1–52% of total sediment P in natural aquatic ecosystems like wetlands and lakes (Qian et al., 2010; Renjith et al., 2011; Rzepecki, 2010), and has not been highlighted as an exchangeable P unless there is a rapid change in sediment pH and dissolution of metal oxides (Renjith et al., 2011). In our study, however, Ca-P content generally decreased over 60   days, whether in the presence of periphytic biofilm or not, meaning that Ca-P in our study was solubilized and released to water. It has been reported that one type of microbe called phosphate solubilizing bacteria (PSB) is abundantly present in waters and sediments and is very effective in solubilizing Ca-P (Fankem et al., 2006; Maitra et al., 2015). Although the exact reasons responsible for the declines in Ca-P content are unknown, in our study dissolution by PSB might contribute to such variation. Thus, investigations of PSB should be included in future work when evaluating P cycling between water and sediment (Maitra et al., 2015).

In the presence of periphytic biofilm, the concentration of Ca-P in sediment increased at the beginning of the experiment (0–14   days). This outcome differs from the change in Ca-P content in the control. Ca-P could be mobilized naturally with the aging of sediment (Froelich, 1988), resulting in an increase of Ca-P content over time. In this study, however, the increase in Ca-P concentration is mainly due to the presence of periphytic biofilm. One possible explanation is that the rise in pH of water resulting from active periphytic photosynthesis favors Ca-P deposition to sediment. Many previous studies have already confirmed that the presence of periphytic biofilm between water and sediment could cause concurrent deposition of carbonate–phosphate complexes, namely the coprecipitation phenomenon, resulting in Ca-P deposited onto the sediment (Dodds, 2003; Jarvie et al., 2002; Noe et al., 2003; Woodruff et al., 1999b).

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