**6. References**


fevers (Salmonella typhi/paratyphi) whose origin comes from the excrements of the patients or healthy carriers (MESSIAEN C.M, 1989). Other bacteria of the Salmonella species can also cause collective intoxications. The periodically endemic Cholera in the tropical countries, maybe transmitted by soiled salads. Also the bacterial dysenteria (Shigella dysenteriae) can be transmitted by soiled vegetables believed contaminated by the excrements. The preventive protection against these diseases is often done by vaccination. But the use of hygienic measures like disinfections with chloramphenicol, bleach into the water or the

The insecticides of biological origin represent an asset but their major disadvantage in addition to their high costs, is their instability with storage. They quickly lose their effectiveness and consequently any competitiveness. But the need for both safe and natural food products while respecting nature and maintaining a healthy environment is a very important concept to be considered in Integrated Pest Management (IPM). IPM can be defined as a combination and the reasoned use of all the methods which makes it possible to control or to maintain the populations of pests to a threshold economically bearable. And if the consumers estimate that the products are of the first rate quality, they will not hesitate to pay for the full price. Finally, one can reach a great effectiveness in the improvement of plants protection by associating the conservation of auxiliary insects with the application of agrochemicals and biotechnology. Our developing countries will be able certainly to benefit

I wish to thank the M'Pouto village of Riviera-Golf in Abidjan City urban farming producers

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E.J. RYDER & WHITAKER T.W. (1976), Lettuce. In "Evolution of crop plants". N.W.

FABIEN SEIGNOBOS, JÉRÔME GOUST. (2000), L'épinard, l'arroche et la tétragone. *Actes* 

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Clés pour la reconnaissance des familles. Prifas Cirad dépt. Gerdat, Montpellier-

potassium permanganate (KMnO4) is of primary importance.

**4. Conclusion** 

from this progress.

**6. References** 

**5. Acknowledgments** 

for their collaborative contribution in this work.

*Barcelone-Mexico*. 498p.

académique 2000-2001. 1p.

*Simmonds edit., Longmann-London.* 215p.

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France. 302p.


**3** 

*1,2Japan 3Vietnam* 

**Differential Efficacy of Insecticides** 

**The Citrus Psyllid on Citrus Plants** 

*1,2Japan International Research Centre for Agricultural Sciences,* 

Citrus greening is a destructive disease of citrus trees in subtropical and tropical regions. The pathogen of this disease in Asian countries, *Candidatus* Liberibacter asiaticus, is transmitted by the citrus psyllid, *Diaphorina citri* Kuwayama (Huang et all, 2004). Since no direct control of the pathogen has been established yet, the current management of this disease relies on the control of the vector, especially by insecticides (Halbert & Manjunath, 2004; Yang et al., 2006). Many studies have been performed to examine the efficacy of various insecticides on the control of psyllids, revealing that neonicotinoids such as imidacloprid or thiamethoxam are very effective on the psyllid (Hayashikawa et al., 2006; Yasuda et al., 2006; Srinivasan et al., 2008; Gatineau et al., 2010; Ichinose et al., 2010a). These insecticides are characterised by their long-continued residue effect on the pest, up to several months (Yasuda et al, 2007), and their reducible effects on the psyllid population can continue even after the concentration of the insecticides is decreased below the lethal level

Important issues in the use of insecticides are 1) how frequently an insecticide should be applied in year, 2) how much the insecticide should be used in each application, and 3) when the insecticide application should be performed in the year. For the third case, insecticides will be unnecessary when target pests are few due to their seasonal activities or other factors that affect the pest population. For example, the application of insecticides in winter in Florida allows the omission of insecticide uses in subsequent several months when psyllids are likely increased (Quresh & Stansly, 2010). On the other hand, more frequent insecticide application may be required for the control of the psyllid in the tropics where the insect can maintain its population at higher densities throughout the year. Gatineau et al. (2010) reported that sufficient reduction of psyllids was attained either by monthly application of imidacloprid or fortnightly application of fenobucarb in citrus orchards of southern Vietnam. The weather in this region is characterised by the tropical climate with

\* Katsuhiko Miyaji1, Kunihiko Matsuhira1, Keiji Yasuda2, Yasutsune Sadoyama2, Do Hong Tuan3,

**1. Introduction** 

(Boina et al., 2009).

Nguyen Van Hoa3 and Doan Van Bang3

*3Southern Horticultural Research Institute of Vietnam,* 

**According to Crop Growth:** 

Katsuya Ichinose1 et al\*,

