Indeed, most of the plants we grow will tend to be selected because they are trouble free, and those that are more susceptible to attack will have fallen by the wayside over time. However, most farmers find it unacceptable that the food crops they grow are disease resistance in plants pdf by pests. Major gene resistances to powdery mildew are derived from M.
Much later it was shown that the cultivar was also very resistant to collar rot and a useful breeding parent for this resistance. Some plants can tolerate the presence of large numbers of insects without being severely affected. This is not very satisfactory however as insects will still cause damage, and in fact further breeding and population expansion of the pest species is supported. Other varieties are less attractive to pests, but this can be difficult to sustain or demonstrate. The most valuable form of resistance is where the pest cannot survive as well on one variety as on another. Further, a cultivar that is resistant to one disease may be more susceptible to another that is equally important. Another drawback to resistance is that depending on the host pathogen system, resistance is sometimes not long lasting as new pathogen strains quickly develop, and further research and breeding is constantly needed.
Resistant varieties are not available for all crops. In addition, commercial seed companies and plant breeders rarely invest resources into developing resistant cultivars for more minor or speciality crops, which often tend to be those of greater interest to the organic grower. In particular they can be especially useful where the threat from specific pests and diseases is high. The table below illustrates a number of pest and disease resistant vegetable crop varieties, although should not be considered comprehensive. Good resistance to powdery mildew. This page was last edited on 12 November 2017, at 22:25.
There are many types of microbes: bacteria, viruses, fungi, and parasites. While most microbes are harmless and even beneficial to living organisms, some can cause disease among humans, other animals, and plants. All types of microbes have the ability to develop resistance to the drugs created to destroy them, becoming drug-resistant organisms. Simply using antibiotics creates resistance.
These drugs should only be used to manage infections. Antibiotics are among the most commonly prescribed drugs used in human medicine and can be lifesaving drugs. The germs that contaminate food can become resistant because of the use of antibiotics in people and in food animals. Because of the link the between antibiotic use in food-producing animals and the occurrence of antibiotic-resistant infections in humans, antibiotics that are medically important to treating infections in humans should be used in food-producing animals only under veterinary oversight and only to manage and treat infectious disease, not to promote growth. The other major factor in the growth of antibiotic resistance is spread of the resistant strains of bacteria from person to person, or from the non-human sources in the environment. Humans developed antimicrobials to destroy disease-causing microbes. The most commonly known antimicrobials are antibiotics, which target bacteria.
Other forms of antimicrobials are antivirals, antifungals, and antiparasitics. Penicillin, the first commercialized antibiotic, was discovered in 1928 by Alexander Fleming. While it wasn’t distributed among the general public until 1945, it was widely used in World War II for surgical and wound infections among the Allied Forces. When Fleming won the Nobel Prize for his discovery, he warned of bacteria becoming resistant to penicillin in his acceptance speech. An antibiotic is a type of drug that kills or stops the growth of bacteria. Examples include penicillin and ciprofloxacin. An antimicrobial is a type of drug that kills or stops the growth of microbes, such as bacteria, viruses, fungi, and parasites.