Contents - Faperta

Pest Management and the Environment 3
Yield loss (%)
90
80
70
60
50
40
30
20
10
0
Wheat Soybean Maize Potato Rice Cotton
Potential yield loss Actual yield loss
FIGURE 1.2 Extent of losses due to insect pests in major crops.
there is now a greater need to develop alternative technologies that will allow a rational
use of pesticides for sustainable crop production. IPM has historically placed great hopes
on host plant resistance. However, conventional host plant resistance to insects involves
quantitative traits at several loci, and as a result, the progress has been slow and at times
diffi cult to achieve.
What Is Available in the Basket and What Can We Do?
Crop production is severely constrained by increasing diffi culties in controlling the damage
by insect pests because of the development of insect resistance to insecticides. Therefore,
there is a need to adopt pest management strategies to reduce over-dependence on synthetic
pesticides. Natural enemies, biopesticides, natural plant products, and pest-resistant
varieties offer a potentially safe method of managing insect pests. Unlike synthetic pesticides,
some of these technologies (insect-resistant varieties, natural enemies, Bacillus
thuringiensis (Bt) Berliner, nucleopolyhedrosis viruses [NPVs], entomopathogenic fungi,
and nematodes) have the advantage of replicating themselves or their effect in the fi eld,
and thus having a cumulative effect on pest populations. Despite being environmentally
friendly, the alternative technologies have some serious limitations, such as: (1) mass production,
(2) slow rate of action, (3) cost effectiveness, (4) timely availability, and (5) limited
activity spectrum. Some of the natural enemies such as Trichogramma, Cotesia, Bracon,
Chrysoperla, and Coccinella, and the biopesticides such as Bt and NPVs, are being produced
commercially. Strains of Pseudomonas, Beauveria, and Metarhizium are also effective in
controlling insects. Natural plant products from neem, Azadirachta indica A. Juss., custard
apple, Annona squamosa L., and Pongamia pinnata (L.) Pierre., have been recommended for
pest control. Several insect-resistant varieties have been developed, but very few are cultivated
by the farmers on a large scale because of lack of sustained seed supply (Sharma and
Ortiz, 2002). However, many alternative technologies are not as effective as the synthetic
insecticides and, therefore, have not been widely adopted by the farming community on a
large scale. There is, therefore, an urgent need to improve:
• Mass production and the delivery system of natural enemies.
• Bio-effi cacy and formulations of biopesticides and natural plant products.
• Production and distribution of insect-resistant cultivars.