California Pepper Commission

EVALUATION OF THE EFFECT OF FOLIAR APPLIED HORMONES TO ABORT YOUNG FRUIT (NAA); TO INCREASE PRODUCTION OF PEPPERS (FOLIAR FEEDING); AND TO CAUSE RED FRUITS TO RIPEN EVENLY AND HARVEST MORE EASILY (ETHEPHON, ABSCISIC ACID), IN BELL PEPPER.

2015

Bill Weir, Ph.D. - University of California

Bob Giampouli - Live Oak Farms

Mike Marchini - Live Oak Farms

Dominic Giampouli- Live Oak Farms

Nathan Sano - Director - California Pepper Commission

Bob Heisey - California Pepper Commission

INTRODUCTION/OBJECTIVES:

Remove young fruits chemically to avoid hand thinning,
To cause all remaining fruits to become red at the same time,
To cause an abscission layer to form in the peduncle of red peppers,
To enhance root development in young transplants,
To evaluate foliar feeding with Stoller products.

METHODS AND MATERIALS:

Indobuteric acid was soil drenched shortly after transplanting.

Naphthalene acidic acid, ethephon, foliar nutrients and abscisic acid were applied by hand sprayers.

TREATMENTS:

Untreated control
NAA
IBA
Abscisic acid and Ethephon
Foliar feeding

Site Location: Live Oak Ranch, Le Grand, California

Host Crop Variety: Classic

Plot Description and Size: Two lines on one row by 10 feet long, replicated 4 times

Experimental Design: Randomized complete block

Application Conditions:

IBA APPLICATIONS:

Date:Mar 20, April 9, 2015

Time:9:00 a.m., 2: p.m.

Wind:Calm, Lite NW

Sky:Clear, Clear

Temperature: Date:66 F, 72 F

FOLIAR FEEDING APPLICATION:

Date:April 17, 2015

Time:8:00 a.m.

Wind:Calm

Sky:Clear

Temperature:78 F

NAA APPLICATIONS:

Date:April 28, May 16, June 5, 2015

Time:2: p.m., 9: a.m., 1: p.m.

Wind:NW, Calm, Calm

Sky:Clear, Cirrus clouds, Clear

Temperature:72 F, 76 F, 88 F

ABCISIC ACID APPLICATIONS:

Date:July 7, 2015

Time:10:00 a.m.

Wind:Lite WNW

Sky:Clear

Temperature:78 F

ETHEPHON APPLICATION:

Date:July 7, 2015

Time:10:00 a.m.

Wind:Lite WNW

Sky:Clear

Temperature:78 F

ASSESSMENTS: Pepper yields

RESULTS:

EXPERIMENT # 1- NAA TREATMENTS

Naphthalene Acidic Acid (NAA) applied three times at a rate of 0.11%, appears to have caused the early fruits to abort compared to an untreated control. Table # 1 shows pounds/acre and 40 lb boxes/acre of non-graded peppers for each of three harvests in all four replications as compared to an untreated control.

Table # 1 - NAA treated yields compared to an untreated control.

The first harvest (June 15) shows 2425 boxes of peppers/acre for the untreated control and 1715 boxes/acre for the NAA treated plots. There were clearly fewer fruits in the NAA treated plots indicating that some were aborted, and small peppers were noted on the ground. The second harvest (June 26) had similar results with NAA treated plots yielding lower than the untreated control. However, the third harvest (July 7) was reversed with the untreated control yielding 622 boxes and the NAA treatment yielding 932 boxes. Although the NAA treatment had more pounds of peppers they may have been smaller since they were set at a later date.

EXPERIMENT # 2 - IBA TREATMENT

Indolbuteric acid (IBA) treatments to new transplants resulted in improved growth and increased yields in 2014. The same test this year did not provide the same results since the untreated control outyielded the IBA treated plots by 1316 boxes/acre. The reason for the reversal is unclear, but it was noted that the 2015 test did not exhibit the extra height in plants that occurred in 2014. Realizing that this experiment was not requested, the researcher simply wished to verify 2014 results. The University of California system requires positive benefits three years in a row before the data are accepted. Table # 2 shows the results.

Table # 2 - IBA treated yields compared to an untreated control.

EXPERIMENT # 3 - FOLIAR FEEDING TREATMENT

Substitute, Bioforge, Sugar Mover and More Power were foliarly applied to pepper plants on April 17th. The plants set fruit well and appeared very healthy all season. Table #3 shows that they did not yield as well as the untreated control during the first and second harvests. However, the third harvest yielded 942 boxes compared to 622 boxes for the untreated control. Total boxes for all three harvests were 5230 boxes and 5068 boxes for the foliar fed treatment and the untreated control, respectively.

ABSCISSIC ACID TRIAL

Abscisic Acid was applied foliarly at a rate of 1.0 gm/l to cause an abscission layer in the peduncle where it attaches to the main stem. The fruits were allowed to turn red and a subjective harvest was conducted. Live Oak Farms personnel, Dominic Giampouli and Mike Marchini were engaged to hand pick peppers and judge any effects that abscisic acid may have had. Knowing that there was little time before the crop had to be shredded, the researcher added 0.1 pt/ac ethephon to hasten ripening.

Subjective results were as follows:

Abscisic acid treated peppers separated cleanly between the fruit stem (peduncle) and the main plant, resulting in a full length stem on the fruit. The untreated control peppers resulted in a short fruit stem broken near the calyx. Placing an index finger under the stem usually remedied the problem of a broken peduncle, but the practice was not necessary in the abscisic acid treated plots.
Less effort was required to harvest peppers from the abscisic acid plots than the untreated control. Simply lifting the pepper slightly was all that was usually necessary.

CONCLUSIONS:

This year's work provided indications that NAA may be beneficial in removing early fruits, but detailed investigations are needed to determine rates and timings to give best results.

Also, foliar feeding with low analysis N and K, and some micronutrients and hormones gave yields greater than the untreated control. The causative element could be identified and isolated, but these same products have given increased yields in almond, walnut, tomato and cotton in the past few years of testing.

Finally, abscisic acid showed some promise in helping to form an abscision layer in the peduncle of red fruit to enhance ease of harvesting. Again, optimum rates and timings will need to be examined.