TABLE 2.

Experimental transmission of S. citri GII-3, GII3-9a2, GII3-9a5, and GII3-11cl to periwinkle (C. roseus) through injection to the leafhopper vector C. haematoceps

ExptInoculantPlantLiving insectsaCFU/ insectbSymptomscCFU/g of midribsd
1SP4 mediumP15
P24NDe
P38ND
GII3 (wild type)P161 × 106+5.7 × 106
P24+ND
P32+ND
GII3-9a2 (Δspi)P1102.8 × 106+ (2)1.2 × 106
P212
P31
P49
P57+ (4)2.3 × 106
GII3-9a5 (spi-gfp)P194.9 × 105+ (7)7.3 × 105f
P210
P34
P47
P512
GII3-11c1 (ori)P157.5 × 105+4.5 × 106
P27+5.3 × 106
P310+ND
P411+ND
P52+ND
2SP4 mediumP18
P21ND
P35ND
GII3 (wild type)P171.9 × 106+1.2 × 107
P27+
P36+
GII3-9a2 (Δspi)P172.9 × 106
P24
P311+ (3)1.4 × 107
P45
P59
GII3-11c1 (ori)P161.2 × 106+1 × 107
P29+ND
P39+9.5 × 106
P49+ND
P59+8.5 × 106
  • a Number of living insects at the end of the 2-week transmission period. All plants were initially subjected to infection by 12 injected insects.

  • b Average of four independent determinations, each from a group of five insects taken at the end of the transmission period.

  • c Numbers in parentheses indicate the delay (in weeks) in symptom appearance compared to that for the control strain GII-3.

  • d Spiroplasma titers were determined at 6 (experiment 1) or 7 (experiment 2) weeks posttransmission.

  • e ND, not done.

  • f In this plant, spiroplasma titers were 2.2×102 and 7.3×105 CFU/g of midribs at 8 and 16 weeks posttransmission, respectively.