Plant protection from pests

There are thousands of kinds of natural pesticides. Plants have been engaged for millions of years in chemical warfare with predators, most of which are insects. They have evolved a wide variety of complex protective mechanisms, many of which are toxic chemicals. Humans have probably known for a very long time that natural products such as uicotiue from tobacco, turpentine from pines, pyrethrum from chrysanthemum species, and quinine from cinchona bark can provide protection from pests and parasites. Our diet contains a large number of such chemicals but ordinarily we have mechanisms to detoxify or excrete them so that they are not a problem. 

There are as yet few published measurements of PI expression levels in pollen. It is therefore difficult to extrapolate from the results of experiments with purified transgene products to making predictions about the effects of GM plants on bees. However, if we assume that the bees in the bioassays described above received a diet which was 25 percent protein, then the doses of Pis administered ranged from 0.004 to 4 percent of total protein received. GM Pl-plants that are effectively protected from pest attack typically have leaf expression levels ranging from... 

Effect on content of polyphenolic compounds Complete protection from stress, however, appears to reduce plant synthesis of polyphenolic compounds, which are known to be produced as part of the plant s inducible resistance response to fungal and pest attack, but are also produced in response to certain abiotic stress factors such as mechanical injury (Feucht and Treutter, 1999). 

Campbell PJ, Brown KC, Harrison EG et al (2000) A hazard quotient approach for assessing the risk to non-target arthropods from plant protection products under 91/414/EEC hazard quotient trigger value proposal and validation. J Pest Sci 73 117-124... 

Systemic insecticides are superior to contact insecticides in many ways. On account of their absorption and transfer in the plant they can deal with insects which might normally remain hidden or protected from the direct spray of a contact insecticide. Many systemic insecticides are specific to certain pests. For example, owing to the insecticide being contained within the plant, parasitic non-phytophagous insects are less likely than the pests to absorb the insecticide. And so ecological selectivity1 comes into play. 

Over the last few decades, safety has become one of the most important topics related to food. From this view, quality control of vegetable raw materials has at first to cover the following issues natural and anthropogenic contaminants (e.g. heavy metals, pollution from industrial and private combustions, not professionally deposited waste products, radionuclides), residues of fertilisers (e.g. nitrate), plant-conditioning and plant-protective agents, filth, pests, the microbial status and the occurrence of microbial toxins. It is not possible to discuss all these aspects in detail however, with a focus on herbs and spices, two of them should be stressed more thoroughly. For further information, see [8]. 

A more recent strategy for protecting plants from pests and disease involves the use of genetically altered plants. This method is controversial. Concerns include cross-pollination with unaltered plants and the entry of altered plants into the food supply. 

Cyclodienes are an important group of chlorinated pesticides. The group hep-tachlor includes insecticides such as chlordane, aldrin, dieldrin, endosulfan, and heptachlor and its epoxide. These are used for the control of a variety of plant pests in agriculture and household environments. The entry of cyclodienes to the global market has created easy management for the control of crop pests. They appeared after World War II as tools to protect food crops and control diseases from pests. In fact, humans were protected from malaria, typhus, and loss of food crops by pesticides. 

The ecological balance is often disturbed by external factors, which may originate from nature or from man s activities. An increased incidence of pests can be caused merely by disturbances due to the weather. Every type of farming thus constitutes interference with ecological relationships and results in plant protection problems. 

Plant bulbs in early autumn as soon as they are available. Handle carefully to avoid bruising, and don t let them dry out before planting. Set bulbs 6" deep in humus-rich, moist, very well drained soil under partial shade. Plants bloom in early spring choose a site that offers protection from late frosts. Water during bloom. Well-grown fritillaries are troubled by few pests or diseases. 

While tending your garden, you may find that the pests that most plague you are not on your plants but on you or your pet. In addition to protecting your garden from pests, some of the control methods in this book offer safe alfernafives to dousing yourself or Fido wifh synthetic chemicals. 

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