2. Larvicidal activity of insect growth regulator IGR and insecticides: 2.1. Insect growth regulator IGR: Bakr, et al. (1984) evaluated some IGR's Dimilin (25% WP), Bay Sir 8514 (6.5% EC), Altosid (10% EC) and RO-08-9801 (50% EC) against Culex pipiens. Results revealed that, all the tested compounds inhibit the moulting process of the third and fourth larval instars with different degrees of morphogenetic changes. The developmental events of pupae died by Dimilin are not completely out of larval exoskeletons and larval-pupal intermediate shows 4th instar larval exuvia attached to the thoracic and abdominal region. The developmental events of adults died as a result of Dimilin and Bay Sir 8514 treatment death occurred before exuviations, right after partial emergence, after incomplete emergence (where pupal exuvia remain attached to thorax and head region) or after incomplete emergence (where the main trunk exuviated but the rest of the adult body is retained within the pupal exuvia. Generally, the observed morphogenetic effects of the tested Insect Growth Regulators were characterized and varied relatively to the type of each compound. The results showed that the sensitivity of larvae to a given compound varied with age. It depends on the insect species and the compound used. Estrada and Mulla (1986) investigated the efficacy of the IGRs-21149, an oxime [O-(2-(4-Phenoxyphenoxy) ethyl propionaldoxime], against 2nd and 4th instar larvae and pupae of An. quadrimaculatus, Ae. aegypti and Cx. tarsalis. The compounds produced an overall mortality or 95% inhibition of adult emergence at 0.0047, 0.0013 and 0.00041 mg/liter in the three species, respectively. The LC95 values for another IGRs-31183, a pyridine compound, [1-(4-Phenoxyphe... ... middle of paper ... ...emboonkeat (1987) reported that an aqueous neem seed kernel extract was less toxic than petroleum ether and alcohol extracts when tested against Spodoptera litura and Plutella xylostella. Addition of 0.1% piperonyl butoxide gave the best result especially with petroleum ether and alcohol extracts. Karr and Coats (1988) evaluated the insecticidal properties of limonene against many insects. Limonene only was slightly toxic. When limonene applied with piperonyl butoxide, synergism was occurred. Limonene also had some repellent activity and fumigant action. Songkittisuntorn (1989) evaluated the efficacy of neem oil extracted substances on the rice leafhopper. The repellent action of neem oil was found increase with increasing of oil concentration. Neem oil reduced the nymph populations. Adding 0.1% piperonyl butoxide as a synergist to neem oil increased mortality.
Stevenson PA, Hofmann HA, Schoch K, Schildberger K. 2000. The fight and flight responses of crickets depleted of biogenic amines. Journal of Neurobiology 43:107-120.
Finally, methanol poisonous wood alcohol that has blinded and killed thousands of converts after ingestion of formaldehyde and formic acid (the main component of the venom of the sting of fire ants). Formaldehyde, a deadly neurotoxin that is stored in adipose tissue, particularly in the hips and thighs, is used to embalm corpses and violent is a carcinogen.
The cigarette beetle is one of the most common household insect that causes damage to stored products such as dried materials of animal and vegetable origin, nuts, herbs, spices, grains and grain products etc. They usually feed heavily at the larval stage (Cabrera, 2007). The insects are also found to develop favourably on root and tuber crops such as cassava, yam, cocoyam and sweet potato mostly in the dried or processed state for storage (Adebayor, 2002). The insect usually infest and contaminates stored products with their cocoons and body parts when they die, thereby reducing the qualitative and quantitative value of the stored product which makes it undesirable for human consumption (Buss and Fasulo, 2006). The rate of development of the cigarette beetle is dependent on the food source and environmental factors such as temperature and relative humidity (Rees, 2004). The longest developmental stage is usually recorded at the larval stage where most feeding is done; the longevity of the adult insect is usually dependent on the type and quantity of food consumed during the larval stage (Papadopoulou, 2006; Mahroof and Phillips, 2008).
Burpee, Lee, and Richard Latin. 2008. "Reassessment of Fungicide Synergism for Control of Dollar Spot." Plant Disease 92.4: 601-06.
The spinosad insecticide is very active and effective in controlling insects and pests. It acts on both contact and ingestion by an insect. The insecticide is subjective to the stages of life of an insect such as larvae or adult stages and the insect species. The insecticide mode of action is through the neural mechanism. It affects the neural transmissions and processes of an insect. Spinosad is applied to field crops during the entire growth process as specified. It is applied to crops such as flowers, vegetables, fruit trees and also cereals. Some flower farmers spray their crops before harvest to rid them off harmful insects (Kole, 1995). Farmers use spinosad insecticide to kill harmful insects that destroy their crops and spread diseases lowering the yield. It is also used to control storage pests that destroy cereals stored in bins. Quality food produce is another reason for the applying the insecticide.
Lawrence, Timothy, and Walter S. Sheppard. "Neonicotinoid Pesticides and Honey Bees." Cru.cahe.wsu.edu. Washington State University, Nov. 2013. Web.
If preventive measures are not sufficient, “insecticides derived from natural plant extracts, natural soap or minerals or plant extracts such as neem, lemon grass, garlic, ginger and many more can be applied” (NP Agricultural Service and Partners Report, 36). Cotton farmers in Benin, for example, show that cotton can be grown without chemical pesticides, notably endosulfan (NP Agricultral Service and Partners Report, 37). Practices that can all be successful include encouraging natural predators, selecting resistant varieties, planting early maturing varieties which reduce the risk of pest attacks, use of rotation and trap crops and the use of food sprays for predators to improve the balance between useful insects and pests. (WHO,
M. Sexta larvae have five phases of their life, called instars, before they start the process of pupation. 81% of the larvae who were taught to avoid EA during their third instars still showed an aversion to the chemical late in their fifth instars, just before pupation (with a p-value of less than 0.001, showing the difference between the fifth instar caterpillars who received the shock during their third instars and the control caterpillars, in terms of aversion to EA, to be significant.) This data was similar enough to the larvae that were both taught to avoid EA and tested for EA aversion in their fifth instars, that it was safe to assume that the differences in the data were caused by random chance (based on a p-value of 0.74) Therefore, aversive cues and behavior persist across larval molts, and the time between third and fifth instars doesn't show a significant difference in levels of response to
To identify truly dangerous plants in Emmet county Northern Michigan, the list of poisonous plants in the ACHS Herb 101 textbook were compared to plants in Emmet county using the Field Manual of Michigan Flora. From the emerging list, eliminations were made based on established medicinal or traditional use, and toxic, allergenic or photo-sensitizing abilities. Finally, by taking into consideration the highest probability of mis-identification or improper preparation; the list of poisonous flora growing in Northern Michigan was narrowed to a legitimate five. From those five, three extremely dangerous plants were chosen: Anticlea elegans (Death Camas), Conium maculatum (Poison Hemlock), and Daphne mezereum (Mezereon).
Pesticides that behave like the female hormone estrogens can have serious effects on reproductive success and function on animal exposed to them. Reproductive success or fitness is defined by having live reproductively capable off...
LaJeunesse, S.. Common crop pesticides kill honeybee larvae in the hive. Penn State | News. 27 January 2014.
How this works is billions of neurons (nerves cells) are placed in the human system and they send electrical impulses to the nervous systems. These impulses control ones movement, feelings, pain, and sensory information and so on. Digging into the neuron, is its components: dendrites, soma, and axon. The dendrites receive signals from other neurons while the axon is the sender. The soma is the body of the neuron. In addition, between the spaces of the neurons are synapses. These contain effector cells, which carry out signals (neurotransmitters) to the next cell or neuron to create a desired action. Now, if the neonicotinoids block a specific chemical pathway which inhibits the communication between the neurons and the central nervous system, then one of these said parts must be affected by the insecticide. The neonicotinoids could destroy the dendrites and/ or the axons because that would prevent the electrical impulses being passed and received. When the central nervous system cannot rely or send any messages to the rest of the body, then it becomes paralyzed. This is how neonicotinoids cause the death of insects and possibly the
The oil from this plant can be used to deter both insect and animal pests from the home. Many people enjoy the scent and have used peppermint oil to not only keep nuisances such as mice, roaches, flies, and fleas out of their home, they have eradicated infestations for good. (4) Peppermint oil is safe to use in homes with children and pets. It is easy to find in grocery stores, in the baking aisle near other flavorings. The scent is strong, compared to other deterrents, peppermint is far more economical.
Pesticide is a chemical used to prevent, wipe out and control the pest problem in agriculture. The use of pesticides have become a common practice around the world, and used almost everywhere, such as agricultural fields, homes, park and school, and so on. Most pesticides are insecticides, herbicides and fungicides that have distinct purposes. Insecticides are used to control insects; herbicides are used to destroy plants; fungicides are used to prevent molds and mildews. Most commonly pesticides contain highly toxic chemical such as Acid copper chromate (ACC), Acephate and Chlorpyrifos, and so on. One of example of insecticides, Chlorpyrifos, sprays widely on a variety of food and golf courses in order to control pests in a cornfield. However, “Chlorpyrifos can cause cholinesterase inhibition in humans; that is, it can over stimulate the nervous system causing nausea, dizziness, confusion, and at very high exposures (e.g., accidents or major spills), respiratory paralysis and death.” (EPA GOV) In the market has thousands of products are similar as Chlorpyrifos.
One of the first reason why insects are so successful because they possess a tough exoskeleton that is covered with a waxy water repellant layer. The exoskeleton of insects also has helped them survive. An insect's external skeleton, or exoskeleton, is made of semi-rigid plates and tubes. In insects, these plates are made of a plastic like material called chitin along with a tough protein. A waterproof wax covers the plates and prevents the insect's internal tissues from drying out. Insect exoskeletons are highly effective as a body framework, but they have two drawbacks: they cannot grow once they have formed, and like a suit of armor, they become too heavy to move when they reach a certain size. Insects overcome the first problem by periodically molting their exoskeleton and growing a larger one in its place. Insects have not evolved ways to solve the problem of increasing weight, and this is one of the reasons why insects are relatively small. But compared to animals the Exoskeletons d...