When individual farmers need help in dealing with pests, pesticide vendors are always prepared to offer some free advice. Of course, because they make money from the sale of pesticides, pesticide dealers have an interest in promoting their products. They have little incentive to recommend pest control practices that don't rely on their particular line of pesticide products. Sales staff may encourage bulk buying by offering lower unit prices per litre or kilogram so that the turnover of products is faster for the distributor. Pesticide end users are thereby often left with products for which they have no valid use and this may result in inappropriate use of pesticides on crops or in situations for which they are not intended; overuse of pesticides; deterioration of products that have been stored for long periods; and damage to inappropriately stored containers. Use of pesticides whose efficacy is reduced by deterioration or adulteration can result in the development of pest resistance that in turn leads to more pesticides being applied in efforts to tackle these pests. Small vendors of pesticides are themselves often ignorant of the danger of pesticides because they have little or no training about pesticides. They fail to protect both themselves and staff working for them in their stores. They rarely provide workers with protective equipment at their work place and have no means of dealing safely with obsolete products such as those that have been damaged, lost their labels, expired or are ineffective. Farmers are certainly aware of pesticide dealers' business interests, but getting an informed second opinion about alternative pest control methods can be very difficult. Many farmers don't feel they can afford to pay for a professional agronomist to visit their farm and national extension services are often severely under-resourced.
At the national level, agrochemical companies or their local agents often take the initiative in advising plant protection services on their pesticide requirements. Because each company has only a limited number of products in its line, the range of options presented may not be the best suited for the country's needs. Also, their assessments may be in excess of actual requirements. These recommendations occasionally form the basis of the countries' requests for pesticide donations and can lead to an accumulation of unused pesticide stocks.
Countries donating pesticides may be motivated out of a desire to provide spin off benefits for their domestic pesticide manufacturers. However, producers in the donor country many not make the most appropriate products for the conditions in the recipient country. Pesticides donated through this type of supply-driven, tied aid are more likely to become obsolete because the specific pest control needs in the recipient country are not the sole consideration.
Large sums of money are involved in pesticide procurement. There is always the possibility that unfair practices will be used to seal the deal. 'Under the table' offers between sellers and officials responsible for pesticide procurement can sometimes influence government decisions regarding pesticide imports.
Government corruption can lead to unnecessary purchases of pesticides. Officials with ties to agrochemical companies may profit personally from increased pesticide sales. They may push for greater pesticide procurement even when there is no demand.