Authors: Kathryn Fontenot, Dennis Burns, Kylie Miller, Whitney Wallace, Andre Brock, Donna Lee, Betsy Crigler, Bobby Williams and Mary Sexton

Introduction:

Summer squash is an important component of the American diet. Summer squash is typically consumed baked, grilled, sautéed or steamed. Americans also eat squash blossoms. Squash is consumed not only for the taste but also for its’ nutritional value as squash is high in vitamin C.

Louisiana producers continuously strive to produce local, fresh and nutritious produce. In 2014, Louisiana vegetable producers grew yellow squash for the fresh and processing market. Zucchini was reported for the fresh market only. One hundred and five producers grew fresh market yellow squash on 194 acres for a gross farm value of $2,230,876. Fresh market zucchini was produced by 43 growers on 35 acres totaling a gross farm value of $312,495. An additional 30 producers grew 94 acres of yellow squash for processing at a gross farm value of $1,045,625 (LSU AgSummary, 2014).

Squash is grown in Louisiana as a spring and fall crop. Seeds do well when direct seeded but many producers also use transplants. Plastic mulch and drip irrigation are recommended for optimum growth and yields. Typical spring planting dates start as early as March 15^th in south Louisiana (earlier if a grower is willing to cover the crop during freezes/ frosts) and generally after April 1^st in north Louisiana. The fall crop is planted June through mid- August. Summer and winter squash are grown in Louisiana. However, summer squash is more widely grown and sold here.

Objective: Nineteen varieties of yellow summer squash were evaluated in the spring of 2016 to determine varieties that perform best in terms of marketable yield under Louisiana environmental conditions.

Materials and Methods:

The 2016 trial was a repeat of the 2015 squash trial; however, the 2016 trial was replicated at three farm locations: Genius Farms in St. Francaisville, Louisiana, Covey Rise Farm in Husser, Louisiana and at the LSU AgCenter Northeast Research Station in St. Joseph, Louisiana. All 19 varieties were planted at each farm. Ten plants of each variety were planted at each farm. Planting dates were as follows: March 15, 2016 at the Covey Rise location, April 5, 2016 at the Northeast Research Station and April 12, 2016 at Genius Farm. Transplants were produced at the Hill Farm located on LSU’s Campus in Baton Rouge, Louisiana. One seed was sown per cell. Jumbo 6-pack cell trays were filled with Fafard Super Fine Germinating Mix. Seeds were fertilized with Peters 20-20-20 twice after the first true leaf emerged at a 200ppm rate. Seeds were started three weeks prior to each field plant date. Preplant fertilizer (13-13-13) was banded at a rate of 500lbs/ acre. Black plastic and drip irrigation was used at Covey Rise Farm. Drip irrigation only at Genius Farm and no irrigation or plastic at the Northeast Research Station. The Northeast Research Station was established to trial row crops. The field we were provided with had no access to water.

Cucumber beetles and plant bugs were the primary insects of concern. The squash was managed with some insecticides and fungicides but the spray schedule, application timing rates and products were different at each location as the three farmers were managed by three different producers. Data collection occurred five times at each farm beginning on May 5, 2016 and ending June 6, 2016. Dates differed between farms. The earliest harvest dates occurred at Covey Rise as it was the first planted trial. At each harvest, squash were graded using USDA standards (U.S. No 1, U.S. No 2 and Cull.

U.S. No. 1 Fruit must meet the following requirements: ''U.S. No. 1'' consists of squash of one variety or similar varietal characteristics, with stems or portions of stems attached, which are fairly young and fairly tender, fairly well formed, firm, free from decay and breakdown, and from damage caused by discoloration, cuts, bruises and scars, freezing, dirt or other foreign material, disease, insects, mechanical or other means.

U.S. No. 2 Fruit must meet the following requirements: ''U.S. No. 2'' consists of squash of one variety or similar varietal characteristics which are not old and tough, but are firm, free from decay and breakdown, and free from damage caused by freezing, and from serious damage caused by discoloration, cuts, bruises, scars, dirt or other foreign material, disease, insects, mechanical or other means.

Table 1 Variety names, type of squash (crook or straight neck), seed source, germination rates and the transplant survival rates up to the first harvest during the 2016 LSU AgCenter Squash Variety Trial.

Results and Discussion:

All seed was purchased fresh. The sterile germinating ix and greenhouse conditions allowed us to achieve 100% germination rates in all varieties. The squash in this trial germinated and grew very quickly. However, once the transplants were placed into the field, external environmental conditions set in, in particularly insects. Lioness was the only squash variety with 100% field survival rate at first harvest. Other varieties with greater than 85% survival rates included Multipik, Solstice, Gentry, Gold Star, Cosmos, Precious II and Superpik. Field survival rates overall were low because of one primary reason. The Covey Rise Location was heavily impacted by cucumber beetles which brought on Erwinia tracheiphila commonly known as cucurbit bacterial wilt. The plants at this trial location went down very quickly despite continuous attempts to manage cucumber beetle populations. This is an important factor producers must consider when growing any cucurbit crops, management of cucumber beetles to prevent total crop loss.

Squash fruit were harvested 5 times at each location representing the first 5 harvests a producer would yield. Of course, the squash continuous to produce beyond the first 5 harvests so a producer can expect higher yields than reported in this study throughout the season. The top three varieties in terms of number of squash harvested include: Superpik, Solstice and Cosmos. All three of the top varieties had 99% or greater USDA No 1 and 2 number of fruit and fruit weight. Although Delta was not among the top varieties in terms of number of squash harvested it was a very dense squash allowing it to produce the heaviest squash making it top for pounds produced of marketable US No 1 and No 2 squash. Superpik was the only squash that was significantly greater in yield in terms of the number of squash harvested. If a producer were looking for heavy weights because he/ she was selling by the pound, Delta is a variety to consider.

Table 2. Total and Marketable Yields in the 2016 Summer Squash Variety Trial.

*Numbers represent mean yield for each of the first 5 harvests of the season. Assuming a producer plants every row 48" wide and spaces plants on 36" centers.

Conclusions:

As a recap, the top producing squash varieties in 2015 included: Solstice (7865 fruit/acre/ harvest), Cosmos (7684 fruit/acre/ harvest), and Cheetah (7321 fruit/acre/ harvest). In 2015 Dixie our control variety produced 5143 fruit per acre per harvest. Because Solstice and Cosmos were once again at the top in terms of production in 2016, the LSU AgCenter recommends producers include these varieties on their farm. Solstice and Cosmos were also above 90% on plant survival rate fro all three farms combined. However almost all Solstice were lost at Covey Rise farm because of bacterial wilt. If you as a producer have battled this disease in the past, consider growing Cosmos only. The main difference besides yield and weights in the top producing squash varieties and Dixie are that both Cosmos and Solstice are straight neck yellow squash whereas Dixie is a crookneck yellow squash. Additionally, Enterprise and Golden delight are actually yellow zucchini. In this study they were harvested small but are still edible and tasty when harvested at 7 inches and longer.

Acknowledgments:

This study was a team effort between local farmers, county agents, vegetable specialist and extension associate. Thank you to Mr. James Genius, Mr. and Mrs. Sandy Sharpe, Mr. Dennis Burns, Mrs. Kylie Miller, Mr. Andre Brock, Mrs. Whitney Wallace, Mrs. Donna Lee, Mrs. Betsy Crigler and Mr. Bobby Williams for helping plant, maintain and harvest the data in this trial.