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Abstract. Pesticides are chemicals that kill or manage the population of pests. There are many different types of pesticides on the market today, but the most common are herbicides and insecticides, which kill or manage unwanted plants and insects. The benefits of pesticides include increased food production, increased profits for farmers and the prevention of diseases. Although pests consume or harm a large portion of agricultural crops, without the use of pesticides, it is likely that they would consume a higher percentage. More food is produced by farmers, thereby increasing profit. Pesticides also increase farm profits by helping the farmer save money on labor costs. Using pesticides reduces the amount of time required to manually remove weeds and pests from the fields. In addition to saving crops and livestock, pesticides have also had direct benefits to human health. It is estimated that since 1945, the use of pesticides has prevented the deaths of around seven million people by killing pests that carry or transmit diseases. Although there are benefits to the use of pesticides, there have also been many problems associated with their use. Pesticides do not always stay in the location where they are applied. They are mobile in the environment and often move through water, air and soil. The problem with pesticide mobility is that when they travel, the pesticides come in contact with other organisms and can cause harm. Pesticides have also been shown to disrupt the balance of an ecosystem. In many situations when a pesticide is used, it also kills non-pest organisms. This can drastically alter the natural balance of the ecosystem. By removing non-pest organisms, the environment can be changed to favor the pest. In addition to causing harm to wildlife, pesticides that travel from their original location are known to cause harm to humans. Human exposure to pesticides has caused poisonings, the development of cancer and the deaths of between 20000 and 40000 people worldwide each year. Another major problem associated with pesticide use is bioaccumulation and biological magnification. Bioaccumulation is when a substance builds up in the body because the body does not have the proper mechanisms to remove it. Many synthetic pesticides are not able to be broken down. Once they enter the body of an organism, they are permanently stored in the body tissue.

Leaf beetles and fruitfly infestation greatly limits water melon (Citrullus lanatus) production throughout the tropics. The efficacy of aqueous plant extracts applied at 5 % w/v concentration of two botanicals (neems seed oil and garlic bulb) and 1.5 melt of one synthetic insecticide (karate 2.5 EC) against their infestation were evaluated. The effects of these treatments including control on the number of the insects, number of leaves, vines, length of vines, number of fruits, fruit weight, fruit damaged and undamaged were assessed during 2012 and 2013 cropping seasons in Lawanti, Gombe state, Northern Guinea Savannah region of Nigeria. Result of the study showed that neem seed oil and garlic bulb treatments at 5 % w/v were effective against the leaf beetles and water melon fruitfly as the synthetic insecticide karate 2.5 EC in managing the water melon insect pests. Karate 2.5 EC significantly reduced the infestation of the insect pests of water melon and increased number of leaves, vines, length of vines, number of fruits, fruit weight and number of undamaged fruits/plot followed closely by neem seed oil (A. indica) and garlic bulb (A. sativum) extracts. Water melon a growth and fruit yields were appreciably improved in these treatment while untreated control water melon crops had more leafs beetles and fruitfly infestations, poor plant growth and lower fruit yields. Both botanicals can thus serve as alternatives to synthetic insecticides for managing water melon leaf beetles and fruitfly attack.

Field experiments were conducted at faculty of Agriculture teaching and research farm, university of Maiduguri in 2010 and 2011 rainy seasons. The aim was to investigate the impact of intercropping sorghum with okra on the incidence of flea beetle of okra (Podagrica spp) in the semiArid zone of Nigeria. The results showed that sole crop okra suffered flea beetle attack which affected its growth, fruit formation, fruit weights and fruit yield. Intercropping okra with sorghum significantly reduced the flea beetle populations, leaf damage caused by Podagrica spp (Coleoptera: Chrysomelidae). While increasing number of leaves for photosynthetic activities, plant height, fruit formation, fresh fruit weight and total fruit yield. The study concluded that okra intercropping at 1:1, 1:2 and 2:2 are the most efficient and productive intercrop systems in flea beetle management. Okra intercropping with cereal sorghum was found to be good for sustainable agriculture and organic farming in Nigeria due to its numerous advantages, particularly with respect to insect pests' control.

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