|Background Information for this page|
|Return to radar list for Middletown RI|
|Chart version of thinner sensitivity ratings|
|Weather data for Middletown RI. Forecast values begin May 20, 2013|
|Estimated Apple Sensitivity to Chemical Thinners|
| Other factors
may outweigh the weather effects use for these estimates. Other
influences include: fruit diameter, fruit exposure to temperatures >=75 F,
pollination, this year's cropload, last year's cropload, warm February-early
April temperatures, frost and prolonged cool and cloudy weather during bloom,
previous fall weather, foliage condition last summer)
Ratings below are for the influence of weather on fruit sensitivity to chemical thinning agents. Ratings assume fruit are less than 13mm diameter. Dates in bottom rows are beyond 18mm diameter for most cultivars, and are intended only for late cultivars. Look at your fruit!
|Rough guess McIntosh King fruit diameter
12mm - May 27, Monday 15mm - May 31, Friday 18mm - June 2, Sunday
|Date after which fruit have exposure to 2 days of daily high temperature of at least 75 F: Friday, May 31|
| Very warm night temperatures (average
> 69F = 19 heat units in table) can lead to "EXCESSIVE THINNING
RISK", especially if combined with cloudy weather, or if combined with
use of NAA.
Warm nights + Cloudy days -----> Increased sensitivity, maximum thinning.
Warm nights + Sunny days -----> Intermediate senstivity, moderate thinning.
Cool nights + Cloudy days -----> Reduced sensitivity
Cool nights + Sunny days -----> Reduced sensitivity, minimum thinning.
Estimates assume morning application.
For afternoon application use rating for next day.
% CLOUD SHADING
on application day and the next two days.
< 20% = "sunny blue sky"
> 40% = "cloudy"
Cloudy weather on 3 days after application increases thinning.
NIGHT HEAT UNITS
= degrees above 50 F for 7pm--7am
for 3 nights after application.
Example: If average night time temperature is 55F, then value = 5.
Values above 10 for three nights after application increases sensitivity to thinning.
Influence of weather on sensitivity of fruit to thinning agents for 3 days following a morning application
Ratings assume that fruit
are within diameter range
of susceptibility for thinning.
95% Petal Fall
Fri, May 17
|sunny 2%||1||Stronger influence for reduced sensitivity|
|100% Petal Fall Sat, May 18||sunny 13%||3||Intermediate|
|Sun, May 19||24%||6||Increased sensitivity|
|Mon, May 20||74%||12||Stronger influence for Increased sensitivity|
|Tue, May 21||77%||10||Stronger influence for Increased sensitivity|
|Fruit Set Wed, May 22||77%||17||Increased sensitivity|
|Thu, May 23||30%||14||Intermediate|
|Fri, May 24||sunny 16%||9||Intermediate|
|Sat, May 25||sunny 17%||7||Intermediate|
|Sun, May 26||sunny 17%||8||Intermediate|
|Mon, May 27||sunny 17%||6||Intermediate -- sensitivity may be less if fruit diameter is >12mm|