Flint and Van den Bosh (1981) define a pest as any organism that diminishes the accessibility, quality, or value of a human resource, such as crop plants. This report specifically focuses on pests with respiratory abilities and mobility. Two specific organisms within the pest category will be analyzed: Greenhouse White Fly and Woolly Aphid. Furthermore, horticultural diseases discussed in this report refer to less active ailments that bear similarities to viruses and growths.
Within the category of diseases, I have chosen to research Botrytis and Apple Scab. One pest that will be discussed is the Glasshouse white fly (Trialeurodes vaporariorum), commonly referred to as the greenhouse whitefly. This particular pest poses a significant problem for various fruit, vegetable, and ornamental crops. It can often be found in glasshouses and other protected horticultural environments. The white flies are small sap-feeding insects with a length of approximately 2mm when fully grown. They possess four wings covered in wax and typically reside on the undersides of leaves. If heavily infested, these pests will take flight together in a small cloud when disturbed.
Infestations can have negative impacts on plants, as documented by The Canadian Journal of Plant Pathology. These impacts include hindering the plants from reaching their maximum potential and resulting in decreased vigor and yields. One example is the potential 25% decrease in yield for a tomato crop if left untreated. White flies typically lay around 200 eggs at once on the undersides of leaves, which then hatch into small nymphs that release a sticky substance called “honeydew” while feeding. This honeydew falls onto lower leaves and forms a black sticky substance similar to soot. Under favorable conditions, white flies are capable of continuous reproduction throughout the year.
The duration of development from egg to adult for Glasshouse whitefly is approximately three weeks at 70 degrees or four weeks at 60 degrees (Buczacki, Harris 1998). While these pests are not usually a problem outdoors due to their preference for warmth, they can be a significant issue for house plants and indoor glasshouse growers. To effectively control Glasshouse whitefly, it is important to maintain cleanliness and clear areas, including the surroundings of the glasshouse during summer where whitefly can utilize weed foliage for their reproductive cycle. In the glass house, common physical control methods involve using simple yellow sticky paper traps placed just above the plants to catch the adults. Biological control can be achieved through the use of a tiny wasp parasite known as Encarisa Formosa, but it requires warm conditions and time to establish its population. Insecticidal soaps can also be utilized to control whitefly numbers while not harming Encarsia formosa. However, other pesticides such as permethrin, bifenthrin, primiphos-methyl, and pyrethrum are hazardous to both humans and beneficial parasitic wasps and should only be employed when whitefly populations have become uncontrollable. It is recommended to apply these pesticides at five-day intervals.
Greenwood P and Halstead A (1997) Woolly Aphid (Eriosoma lanigerum) This aphid is a significant pest to apple growers and orchard owners in the UK. It attacks a number of woody plants, including ornamental Malus and Pyracantha. Unlike most other aphids, woolly aphids suck sap from woody stems rather than the foliage. They are blackish brown in colour and cause galling of the wood. Although they are not usually very damaging to more mature trees, they pose a serious problem for young saplings. Woolly aphids are particularly fond of attacking the thinner bark areas on trees.
Numbers are a problem in both new and old orchards as they can easily enter through freshly pruned branches or cracks in the bark. The woolly aphids feed on the bark, causing soft and lumpy growths on affected shoots. These shoots are visible during winter pruning. The young aphids find shelter in the bark and become active in March and April, secreting a waxy wool material. This material can contaminate foliage and fruit, causing inconvenience during harvest time in late August.
The substance offers protection against predators while the aphids, in small groups, consume young leaf buds and shoots. Infestations are primarily spread by crawling from one tree to another or can be blown from one tree to another under the right conditions. Alford D 2000 mentions that some winged forms appear in July, but they are usually rare. Multiple hatching events of flightless aphids occur during the summer. Young aphids seek shelter lower down in cracks of bark or near the ground, taking cover under the roots and surrounding foliage.
In autumn, the old adults of the Woolly Aphid become dormant until the following spring, dying out as winter approaches. Control measures for Woolly Aphid include physical treatments on fruit trees. During early to mid-winter when the plants are dormant, a tar oil wash can be applied. In summer, Malathion can be used against the young nymphs. Another environmentally friendly approach is to wrap grease bands around affected trees. These bands trap the grubs as they descend the trees in search of hibernation spots near the base or on the ground in autumn. The bands can then be removed in November and burned.
In the 1920’s, a Biological control called Aphelinus, a small parasitic wasp, was introduced in southern England to control Woolly Aphids. If these wasps are present in the aphid colonies, it is recommended to carefully limit the use of pesticides to avoid damaging the wasp populations (Buczacki, Harris1998). Despite limited empirical information on the extent of damage caused by Woolly Aphids, they pose a threat to the overall health and vitality of fruit trees, particularly young ones. The damage inflicted by Woolly Aphids can lead to cankers and result in poor crop yields.
Ultimately, the decrease in production would necessitate either replacing affected trees or removing damaged branches. Diseases such as Botrytis are caused by various infectious agents, including fungi, bacteria, and ‘virus-like’ organisms. These disease-causing agents are referred to as pathogens. Fungi consist of over 100,000 species and acquire nutrients by externally digesting material, distinguishing them from plants. They secrete enzymes into the material and subsequently absorb and digest the mixture.
Most fungi have the ability to produce both sexual and asexual spores, allowing them to rapidly multiply under favorable conditions. Pathogens can develop in various ways, with some only causing minor localized issues like spots on leaves. In contrast, others can completely cover and decay plant material, leading to the destruction of the entire plant, its fruits, and seeds. Botrytinia, commonly known as botrytis, is a highly destructive grey mold fungus that poses a significant problem for soft fruit growers and vineyards worldwide.
Botrytis spores are always present in the air and can survive for up to 30 weeks in dead plant tissues. These spores form black resting structures called sclerotia, which help carry the fungus during periods when there are limited living host plants. If certain conditions are met, such as plant damage or damp and humid weather, the spores can attack and infect live plants, particularly their fruits and flowers (Philip, A etal 2007).
Botrytis, also known as grey mould, is a type of fungi that can invade plant flowers and remain inactive until the fruits start to ripen. When the sugar levels increase during the ripening stage, the fungi can quickly reproduce and create a grey mould on the surface of the fruit. Botrytis flourishes in warm and humid environments typically found in glass houses and polytunnels. To prevent its spread, it is crucial to ensure adequate ventilation in enclosed growing areas. One prevalent variety of botrytis is called botrytis cinerea.
Botrytis, a fungal disease, thrives in damp and humid conditions and can impact various plants. It particularly targets soft fruit that easily rot. Moreover, it can penetrate cracks in woody barks on raspberry and gooseberry stems, leading to die-back. If left untreated, the affected plants need to be completely removed and burned. Other common types of botrytus include B. elliptica which affects Lilly bulbs when it is damp, and B. paeoniae which specifically infects Peonies at the joints where lower leaves meet the stems. This causes brown leaves and mold to appear at ground level. In Europe, stored onions are widely affected by B. allii.
After approximately 10 to 12 weeks in storage, the bulbs become softer and develop brown patches. To prevent this issue, onion ‘sets’ can be treated with dust before planting. B. fabae, which is commonly found on broad beans, causes chocolate brown spots to appear on the leaves, especially on the upper surfaces. This often leads to the patches turning black, and the bean pods becoming infected. As a result, grey mould appears on the pods. In temperate climates, the cold winter weather helps control botrytis by disrupting its life-cycle process and reducing the multiplication of the botrytus fungi.
Most species produce hardened ‘overwintering spores’ as the climate cools. To improve control over fungal outbreaks in future seasons, it is important to prevent the development of these spores along with winter frost. However, when using antibacterial chemicals to combat fungi, it is crucial to bear in mind that repeated use can result in the emergence of mutated and stronger bacterial strains, which may pose problems for humans and other living beings.
The economic impact of botrytis cinerea is significant. This fungus causes damage to grapes in vineyards in France, resulting in a loss of 15-40% of harvests, depending on climatic conditions. This damage accounts for approximately 20% of worldwide harvests in vineyards and is estimated to cost between 10-100 billion Euros annually. Similar losses are also observed in other crops such as strawberries in Spain, where around 20-25% of the crops are affected, and the cut flower industry in Holland, where about 20% of the flowers are impacted. More information can be found on www.genescope.cns.fr about Apple Scab caused by Venturia inaequalis.
Blackish Brown scabby patches appear on fruits, while similar greenish brown spots develop on leaves. The fruits may end up covered with scabby patches and eventually crack or split, becoming vulnerable to secondary problems such as brown rot. Additionally, trees affected by this fungus usually shed their leaves early. The cause of both issues is a closely related fungus that survives the winter on young stems, fallen leaves, and any fruit left on the orchard floor. It is believed that the lack of pruning during damp seasons promotes the spread of this disease due to overcrowded branches.
The suggested controls for Apple Scab, according to Buczacki & Harriss1998, involve improving hygiene by raking up and burning infected leaves to break the fungus’s overwintering cycle. Regular pruning of overcrowded trees is also important, with attention given to removing scabby and swollen shoots. Commercially available anti-fungal sprays like Sovran (kresoxim-methyl) from BASF Company and Flint (trifloxystrobin) from Novartis Company may help combat scab. However, these measures may have limited effect due to the fact that fungal apple scab spores are carried by wind and can spread from tree to tree in orchard situations. (RHS Apple Scab)
Reference Page
Adams C. Bamford K & Early M. 2012 Principles of Horticulture. Oxon UK: Routledge
Alford D 2000, Pest and Disease Management Handbook. Blackwell Science Ltd. Oxford
Baily,A. Chandler, D. Grant, W. Greaves J. Prince G. Tatchell M. 2010 Biopesticides Pest management and Regulation, Oxford: CAB International
Botrytis Reaserch Website – www. Genescope. cns. r http://www. genoscope. cns. fr/spip/Botrytis-cinerea-estimated-losses.html [accessed 18 October 2012]
Buczacki, S. Harris, K. 1998. Pests Diseases & Disorders of Garden Plants, London: Harper Collins
Canadian Phytopathological Society http://phytopath.ca/journallinks.shtml [accessed 27 November]
Flint,M. L and Vanden Bosh, R 1981. Introduction to Integrated Pest Management, New York: Plenum Press
Greenwood P and Halstead A 1997. The royal Horticultural Society. “Pests and Diseases”. The Complete guide to preventing, Identifying & Treating Plant Problems.
The text provides information about the epidemiology of Botrytis cinerea in orchard and vine crops, as well as references to resources on apple scab and wooly aphids. The links to these resources were accessed on 25 September 2012.
The Most Valuable Gift You Can Give Another Is A Good Example
The most valuable gift you can give another is a good example. It might be true that there are 6 billion people in the world. Nevertheless, what you do makes a difference. It makes a difference first of all in material terms. It makes a difference to other people. People and their personal experiences provide us with many opportunities for learning. Among the variety of experiences of others there are two valuable sources of information. They correspond to two different categories of people, who are going through the same experience, come to a surprisingly different results.
Every day we are under the influence of representatives of both groups. One of them is an example to be followed, and the other is an example of what to avoid, it should be studied, but not copied. There are many proverbs telling of the value of good example in influencing others. One can be influenced for good by the good example of others. Yet I think many people learn a lot more from the bad example of others. I think that in my case I have been more influenced for good by the bad example of others than from the good example.
I remember when I was little I saw faults in the conduct or character of others and remind myself not to make that mistake, act that way, be guilty of that. I noted the bad behavior and it was a lesson for me. Most of us have a lot more bad example around us than good example so it is the bad example from which we are more likely to learn. Sometimes we can notice different things in the character of others such as maliciousness, argumentativeness, dishonesty, laziness, etc. it can be a sort of object lesson for us on how not to behave.
It is true too, of course, that bad example can influence people towards badness. One person sees badness and is repelled by it and it is an object lesson to him on how not to behave; another person sees the same badness and is attracted to it and copies it. Especially children learn by copying what others do. By watching and imitating others, young children learn how to interact socially. The examples set by adults, older siblings and children are the most powerful influences shaping a child’s behaviour and personality.
If adults shout, behave violently, exclude or discriminate, children will learn this type of behaviour. If adults treat others with kindness, respect and patience, children will follow their example. If mothers and fathers treat each other with love and respect, this is what their children will learn and most likely ‘replay’ in their adult relationships. One more example: Observing the behavior of people at a traffic light, you notice a different reaction of people’s to the same signal for all, in this case – a red light, and how it depends on the behavior of others.
If the head of the crowd several people stop, usually so do the others. If there would be a madcap, who will make a run across the road , surely there will be followers. In consideration of this , it should be remembered that, breaking rules of road – you set a dangerous example. And if there are children …. They absorb everything like a sponge. People learn in a variety ways. Some ways make a bigger impression on a person than others. So your good deeds may be a good example for all. That’s why the most valuable gift that you can give another is a good example.
The High Cost Of High-Tech Foods
1. What are the ethical issues in this case?? The ethical issues in this case revolve around the consumption of genetically modified (GM) foods. We have the supporters of GM food arguing that judging the actual risk should not occur until extensive scientific research has been conducted. Until then, they believe that these crops can effectively aid in feeding the world’s needy by providing higher per acre yields while having a reduced need for pesticides and herbicides. The Anti- “GMers” present another view, as they fear the supporters are expecting too much from GM food.
These opponents of GM insist on further long-term studies on the effects on the environment; dangers to wildlife and plants; how it will affect the food chain in regards to control of the gene flow prior to any wide distribution. 2. Do you think either group, pro-GM or anti-GM foods, is correct while the other group is wrong? If so, what reasoning do you give for supporting the position of one group over the other? Is it possible for both to be right? What ethical concepts help you decide? As I consider the conventional approach in this scenario I find that both sides present very convincing arguments that cannot be ignored.
Under a principles approach, I certain think that society as a whole has an obligation to ensure our survival and both sides are fighting specifically for that. As such, both sides are correct and both sides need to concede to the other. The Pro-“GMers” must respect and satisfy the concerns and expectations of the Anti-“GMers” while the Anti-“GMers” must respect and confide in the processes the Pro-“GMers” undertake to resolve the conflicts associated with this uncharted territory. 3. Is there any way to bridge the gap between these groups? If so, what would the advantages and disadvantages be??
As mentioned in the previous question, both sides of this debate must strive to develop a synergy that will allow them to work together on resolving the issues and concerns of genetically engineered food. The advantage to this would be that both sides would realize the concerns and address them better as they seek answers together. This process would most likely reduce apprehension while increasing confidence in the process and results. A major disadvantage would stem from those whose goals remain to undermine the process regardless of results.
Both participants must remain open-minded and willing to reason. Those few that are not open to truly considering the evidence will most certainly provide misleading direction and insight that only cater to their goals. 4. If you were crafting GMO public policy, what would you recommend? Speaking in layman’s terms, as I am by no means an expert on all the areas that GMO is associated with, I would craft a policy that ensures transparent testing within all areas of concern. I would expect several layers of policy policing in regards to watch agencies and regulatory oversight.
Neither side of this argument can disagree with the other as we already see the effects of something effecting our environment. With everything from children’s accelerated growth rates, to global warming, we continue to affect our environment. GMO policy needs oversight, transparency, openness, honest results, and willingness to cooperate. 5. Do hybrid seeds represent as serious a concern as that represented by GM foods? What policy would you recommend for hybrid seeds and vegetables? As for whether hybridization is deemed a serious concern, that remains more of a personal, philosophical choice.
With hybrids accelerated growth rate and robust disease resistance, it is easy to understand the appeal for commercial growers or that or a stricken environment such as Haiti in this case. On the other hand, the use of hybrid seeds results in a dependence of the seed provider as a majority of hybrids are sterile and do not reproduce. There are limited concerns as to the effects these hybrids have on the human body, as the majority of concerns are dependency related. Given this, policy on the use of hybrids would mimic that of GMO as both effect our environment just in slightly different ways.