Mites Inhibiting Guava Trees and Their Dynamics in Relation to Weather Factors and Plant Phenology

Document Type : Original research articles

Authors

Plant Protection Research. Institute , ARC., Giza, Egypt

Abstract

Surveying  mites associated  with  guava  trees  (Psidium  guajava  L.)  at Qalyoubia governrate,  Egypt  indicated  the occurrence  of main  five  ones  (i.e.  the  eriophyid,  Tegolophus  guavae  (Boczek),  the  tenuipalpid,  Brevipalpus  phoenicis (Ceijskes),  the  tetranychid,  Tetranychus  urticae  Koch,  the  phytoseiid,  Amblyseius  swirskii A.-H.  and  the  stigmaeid,  Agistemus  exsertus  (Gonzalez)).  Other six  species were  present  in low  numbers.  The  population  dynamics  of  the  main ones  in  relation  to  weather  factors  and  guava  plant  phenology  were discussed.  Populations  of T. urticae  peaked  in  mid-Jun,  and  Oct. as  183.56  and  172.94  motile stages/leaf,  respectively. B.  phoenicis  was observed  at high  population  level in Jun.  and Jul. on  fruits  and  leaves,  respectively. T. urticae  population  peaked  in  Jun. T.  guavae  preferred the  east  side of  the  tree.  Significant  relation  occurred between  mite's  populations  and  temperature  increases;  while  the  relation  with relative  humidity  was  not  significant.  The dynamics  of the  phytophagous  mites' population  densities  (as  second trophic level)  seemed  to  follow  the  plant  phenology  (specially  the  leaves).  That of  the  predacious  mites seemed  to  follow  their prey dynamics  with  lag  of  time.  T. guavae  population  was more significant  on upper  tree  level  than  middle  followed  by lower  one.  Younger  leaves  and lower  surface  were  preferred to  this mite than  older ones  and upper  surface.

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