Yield losses by Phytonematodes: challenges and opportunities with special reference to Egypt

Plant-parasitic nematodes (PPN) constitute a major constraint to agriculture.
Estimates of their crop-loss are important for establishing research, extension, and
budget priority. Regulatory policy action, pesticide impact assessment, resource
allocation, and program prioritization are usually contingent upon such crop loss
data. Recent questionnaire results of important PPN genera and estimates of crop
losses in Egypt due to PPN are presented herein. Crop losses due to the
nematodes on 80 crops, 15 of which are ‘life sustaining’, were estimated at L.E.
15.85 (= $2.30) billion annually based on 2011-2012 Egyptian production figures
and prices. Crop loss estimates of vegetables, fruits, and field crops demonstrated
staggering figures and therefore nematode problems warrant considerably more
effort and support than they are currently receiving. Current challenging nematode
issues include reduced number of effective nematicides available and limitation in
their use due to environmental issues, increased adoption of intensive agriculture,
climate change, occurrence of resistance-breaking PPN pathotypes on
economically important crops, and potential introduction of quarantine-nematodes.
Therefore, basic and applied nematological research should be more oriented to
provide better management of plant-parasitic nematodes in an economically and
environmentally beneficial manner.