EFFECTS OF Tetranychus urticae AND Phytoseiulus persimilis (ACARI: TETRANYCHIDAE: PHYTOSEIIDAE) ON THE CHLOROPHYLL OF ROSAL PLANTS (Rosa sp.)
Tetranychus urticae Koch (Acari: Tetranychidae) is the main pest in rose (Rosa sp.) (Rosales: Rosaceae) by reducing the amount of chlorophyll in plants and at high densities they are overexploited and even killed. One of the most used biological controllers for this pest for its high efficiency is the mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). Our hypothesis was: P. persimilis reduces the populations of T. urticae and therefore chlorophyll is not affected. The objectives were: 1) to determine the susceptibility or resistance of rose varieties to the attack of T. urticae, 2) determine the relationship between the condition of the plant and the population density of T. urticae, 3) know the predation effect of P. persimilis in the control of T. urticae and its efficiency; and 4) determine in which variety of rose P. persimilis performs best. We established the experiment in two parts; the first was one-way and the second consisted of repeated measurements to analyze the effects of T. urticae and the release of P. persimilis through the chlorophyll content variables in SPAD cm-2 units, percentage of damage per cm2 and the number of mites per cm2 in rose varieties. We did three repetitions for each stratum (upper, middle and lower) by variety of rosebush per week, for which we analyzed 72 samples per variety. The varieties of rose evaluated were Virginia and Ojo de Toro. At random we released 100 T. urticae and 12 P. persimilis mites per plant. The data analysis was one-way ANOVA and repeated means, simple linear, multiple and non-linear regressions to determine the dependence between the variables. Prior to the release of P. persimilis there were significant differences between the varieties with respect to the abundance of T. urticae per cm2 , but not in the chlorophyll content and percentage of damage. After the release of P. persimilis, the abundance of T. urticae was different in the strata of both varieties. The Ojo de Toro variety had the lowest chlorophyll content. There was no difference in the percentage of damage and the abundance of P. persimilis between both varieties. Phytoseiulus persimilis was more efficient in the Ojo de Toro variety than in the Virginia variety. It also reduced the damage by T. urticae but did not prevent the reduction of chlorophyll content by the phytophagous.
| Main Authors: | , , , , , |
|---|---|
| Format: | Digital revista |
| Language: | spa |
| Published: |
Colegio de Postgraduados
2018
|
| Online Access: | https://www.agrociencia-colpos.org/index.php/agrociencia/article/view/1712 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|