Chlorophyll meter

Leaf chlorophyll concentration: It was determined by using a chlorophyll measurement device (Chlorophyll meter, SPAD-502, Konica Minolta).
3. Leaf fresh weight and Leaf dry weight (g.Leaf -1 ): Leaf fresh weight and Leaf dry weight were determined according to the method described by Al-Sahaf (6) and Gobara (13) .
4. Petiole length (cm): by using metric tapeline line.
5. Internodes length (cm): by using metric tapeline.
6. Shoot length (cm): by using metric tape.

To determine the effects on onion plant growth, five leaves were selected from the central third of each plant and treatment to measure the chlorophyll content (Minolta SPAD 502 plus chlorophyllmeter) every 15 d, recording the average per plant, expressed in SPAD Units. At week 14, when maturity was reached, the foliar area was measured, expressed in cm 2 were done, with a CI 202, Bio-Science Inc. The fresh and dry plant weights were quantified using an electronic balance (Acculab VIC 612 -0,01 g precision). The plants were dried for 48 h at 70ºC in a Memmert oven.
In addition, soil samples were taken with a metal cylinder,10 cm diameter and 5 cm depth. The samples were transported in plastic bags to the laboratory, where the mites were extracted with a modified Berlesse funnel (Oliveira et al., 2000) . Each sample was observed with a stereomicroscope (Leica microsystems) to confirm the presence of the Mesostigmata mites. The variables were measured in the laboratories of Biological control and Plant physiology of the UPTC.
The data were subjected to normality and variance homogeneity tests using Shapiro-Wilk and Bartlett tests, respectively. When the assumptions were verified, the variables that had statistical differences were tested with Tukey's comparison of means (P≤0.05). The analyses were carried out in R (version 3.3.2).