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Trial insect management system for pecans

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Title:
Trial insect management system for pecans
Creator:
Ball, J. C.
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Agricultural Research Center, IFAS, University of Florida
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Language:
English

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University of Florida
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Copyright Board of Trustees of the University of Florida
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154027052 ( OCLC )

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AGRICULTURAL RESEARCH CENTER - MONTICELLO Monticello, Florida
<7 07
Monticello ARC Research Report 1978-3 May 22, 1978


TRIAL INSECT MANAGEMENT SYSTEM FOR PECANS

J. C. Ball, L. A. Halsey and T. E. Crocker of


Rationale for Pest Management

Prior to the late 1940's the number and effectiveness of pesticides available to growers was limited. Because of this, treatments were keyed to the lifecycle of the insects and their most vulnerable stage or period. The advent of the "modern" organic pesticides, however, seemingly freed the grower from such
constraints on timing. The new chemicals such as DDT, dieldrin, parathion, etc.
were so effective and had such broad spectrum of activity that growers could apply
them at protracted intervals and still achieve unheard of control. In this
manner, timing for the pest became less important (critical) and it was expedient
to schedule sprays by the calendar to facilitate planning and efficiency of the farm operation. Unfortunately, this ideal situation was not to last, terminated
by the natural resilience of biological systems. Pests developed resistance to
the chemicals and others, not previously important, became pests when their
natural enemies were killed by the pesticides. In response, growers began applying pesticides at shorter intervals and higher rates. Resistance and
secondary pest outbreaks were hastened while costs increased and control decreased.
In a way we have come full circle. Because of increasing costs through
factors mentioned above, we once more must match treatments to the life cycle
of the pest and ideally only when the cost of treatment is justified by a greater
loss from damage. Preliminary trials in Alabama and Georgia on managing insect
pests in pecans, basing treatments on pest levels rather than calendar intervals, have shown a reduction in spray cost without reduction in yield or quality.
Presently, we do not have economic thresholds for the pecan insects,
because information is lacking on the amount of damage done. The treatment
levels suggested are designed to give a large margin of safety. For the most part, levels and sample size have been extracted from the Alabama and Georgia
programs. As our experience increases and more information is gathered, these
levels will probably be revised upward.

Brief Biology of Major Pests

Pecan Nut Casebearer: The nut casebearers overwinter as small larvae in
cocoons attached to buds of the pecan tree. In late winter and early spring
the larvae. leave their cocoons and feed on buds and developing shoots. Adult
moths from this generation emerge in late April and May and egg laying coincides with the time that young nuts first appear. The small flat eggs are laid
on the nuts near the blossom end."and, upon hatching the larvae will feed on buds


1 Assistant Entomologist (ARC, Monticello),'County,.Extension Director (Jefferson
County), and Associate'Extension Horticulturist (Fruit Crops Department
Gainesville), respectively.





before entering the nuts. Generally, only one egg is laid per cluster. This is the most destructive generation because a single casebearer larva can destroy several nuts or even the entire cluster. In later generations the nuts are large enough so that a larva will complete its development in a single nut and treatment is seldom required. The larvae (worms) are dark gray with a black heads. Damage is characteristic and easily recognized because of the mass of borings and excrement held together on the outside of the nut by a loose mat of silk.

Yellow Aphids: Yellow pecan aphids overwinter as eggs on the bark of the pecan tree. Eggs hatch in the spring and the nymphs move-onto the foliage. As the name implies, nymphs and adults are yellow in color. The youngest nymphs are extremely small and easily overlooked. Feeding is confined to the leaves and almost exclusively to the lower surface. Development is rapid and there are many generations a year. There appear to be two population peaks a year: one in late spring and early summer, another in late summer or fall. The actual effect of yellow aphid feeding is unclear, but it does appear that heavy populations can reduce nut size and quality. These aphids produce
copious amounts of honeydew, which, if not washed off by rains, supported growth of a black, sooty-mold fungus. Sooty-mold does not harm the plant directly, but by blocking light coming to the leaves, it reduces the plant's ability to manufacture nutrients.

Hickory Shuckworm: The hickory shuckworm is principally a pest of the more mature nut. Shuckworms overwinter as larvae and pupae in old shucks on the ground and in the trees. Adult moths emerge in late winter and early spring before there are nuts on the pecan trees. These adults fly to hickory and their larvae feed in the hickory nuts and phylloxera galls. Adults from this generation move back to pecans. Larvae feed inside developing nuts and in the shuck after the shell has hardened. Generally, larvae destroy few nuts in June, but in mid summer heavy nut loss can occur. Before shell hardening, attacked nuts drop from the trees. After the shell has hardened, feeding is confined to the shuck which may result in poor kernel development and adhesion of the shuck, which blackens the shell and makes removal difficult.

Black Aphid: The black pecan aphid, although present on the foliage
throughout most of the growing season, generally does not build up to damaging levels until late summer and fall. Black aphids apparently secrete a toxin that causes a yellow spot around the feeding site which gradually enlarges and eventually turns brown. Enough spots will cause the leaflet to drop. Because of the time of occurrence, the consequence of defoliation caused by black aphids is greatest on the next year's crop, precluding adequate nutrient storage for nut set. Like the yellow aphids, the youngest stage of the black aphid is barely visible to the naked eye, considerably smaller than a pin head. The nymphs are greenish brown and the adults are dark with prominent black tubercles. Black aphids do not form large colonies but are found scattered on both upper and lower leaf surface.

Pecan Weevil: Adult pecan weevils emerge from the soil in late summer
through fall in north Florida. Adults feed on the nuts, but eggs are not laid until the shell has hardened and the kernel tissue begins to solidify. One to several eggs will be laid in a single nut. The white, grub-like larvae feed exclusively on the nut kernel. When the larvae have reached full development, they chew a circular hole through the shell and enter the soil. Normally, these larvae remain inactive in the soil until the second year when they change to adults and the cycle starts again.









Sampling Program and Treatment Levels.


Pest Species


S~imn1~ Si7P1


Trnnmcnn+ I I


April - July 1


Nut Casebearer


20 clusters per tree 2 5-10% of trees in
small orchard.


Eggs found on 5% of clusters.
Treat when majority of eggs in red ring stage.


Blacklight - trap
2 lights per orchard.


Helps time egg sample and treatment. 4 moths per niqht.


Yellow Aphid


10 compound leaves


30 aphids per comn-


July 1 - October Hickory Shuckworm Blacklight trap - 2 6 moths per night per
traps per orchard. trap.
Yellow Aphid 10 compound leaves 10 aphids per leaf.
per tree.
Black Aphid 10 compound leaves 1 aphid per leaf.
per tree.
Pecan Weevil Screen cages, burlap When weevils present
bands sticky and shells have
bands~ hardened.

1 Pecan cultivar and location in the orchard can effect the levels of a particular
pest species. Therefore sampling should take this into considerati ,on. Divide
the orchard into quadrants and sample an equal number of trees from each quadrant.
Sample each variety, if possible, in proportion to their numbers in the orchard.
Mark the trees with flagging or other easily seen material at the beginning of the season and sample the same trees throughout. Sampling should be conducted
twice a week.
2 Completely circle tree, randomly selecting clusters that can be reached from the
ground. Clusters can be examined without removing from the tree.
3Circle tree, randomly selecting leaves. Inspect lower leaf surface taking care
not to dislodge aphids.
4Circle tree, randomly selecting leaves. Examine both upper and lower leaf surface. 5To be done only in orchards known to have weevil problems. For weevil sampling, select trees that have had heavy infestations. The grower should choose the sampling technique that is easiest for him to work with - see "Sampling Adult Pecan Weevils" by W. W. Neel and M. Shepard. S. Coop. Ser. Bul. 208. 1976.


(Spray materials and rates can be found in: "Pecan Insect and Disease Recommendations" by J. C. Ball and W. J. French. ARC, Monticello Res. Rept. BB1978-2.)


Ti me





tj 0 V ?, 19701 om 2 * *"







AGRICULTURAL RESEARCH CENTER - MONTICELLO Monticello, Florida

Monticello ARC Research Report 1978-4 July 26, 1978

COMMERCIAL PEACH AND NECTARINE VARIETY RECO EHUM~ LIBRARY

C. P. Andrews and C. E. Arnold 1 2 OCT 23 1978


Commerical peach production in north Florida would ~.~oible without varieties adaptable to our area. Peaches grown in notW tfFM
volume shipments of the season. Yet, the number one problem affecfth pan~ industry is the lack of better adapted varieties. Peach and nectarine cultivars currently recommended for north Florida range in chill requirements from 450 to 750 hours below 450F (70C). Another factor influencing this industry is the earliness of fruit ripening. For maximum profits, peach and nectarine varieties should ripen before those grown in the large production areas of Georgia, South Carolina and California while fruit quality must be acceptable on northern
commerical markets.

Peach Variety.Recommendations

Figure 1 illustrates the order and time of ripening of 14 peach varieties in a normal season.- 'Camrden' starts the season the last week in April while 'Loring' is the last cultivar ripening in mid to late June.
'Camden' ripens in late April but fruit size has been small, averaging 1 3/4 inches in diameter or 55 grams. Fruit are yellow fleshed with a 60% exterior red blush. Fruit'are round with a prominent suture, clingstone with good firmness and average flavor. 'Camden' is recommended for trial or limited plantings only. Its chill requirement of 750 hours is considered marginal for north Florida. Fruit should be thinned early and heavy.
'Springbrite' ripens in early May. Fruit size has been small to medium,
1 3/4 to 1 7/8 inch diameter (70 g.) with early and heavy thinning. Fruit are attractive, having an 80% red blush, yellow flesh, round with a suture and tip and semifree. It is recommended for north Florida having a chill requirement of 650 hours but should be thinned properly.
'Springcrest' ripens in early May but fruit size has been small, 1 3/4 inch diameter or 57 grams. Fruit have a 70% red blush, yellow flesh, round with a tip and clingstone. 'Springcrest' has good firmness with average flavor. Quality of many early varieties is not as high as those ripening later in the season. 'Springcrest' (700 hours) is recommended for trial planting but should be thinned early and heavy to increase fruit size.
'Flordaking' ripens in early May with 'Springcrest'. Fruit are large, 2 to 2 1/4 inch diameter (100 grams). Fruit have a 70% light red blush, yellow flesh, round with a suture and clingstone. 'Flordaking' should be planted on warm sites since its chill requirement is 450 hours.

1 Assistant Horticulturist and Associate Horticulturist.
2 This research report was prepared in collaboration with T. E. Crocker,
Extension Horticulturist.








'June Gold' ripens in mid-May and is the leading variety grown in Florida. Fruit are large, 2 to 2 1/4 inch diameter (105 grams), yellow fleshed and have a 60% red blush. Fruit are round with a tip and have good firmness and flavor. 'June Gold' is recommended for north Florida with a chill requirement of 650 hours.
'Maygold' ripens in late May with medium size fruit, 2 inch diameter (80
grams). Fruit are round with a tip, 50% red blush, yellow fleshed and clingstone. 'Maygold' is recommended for north Florida with a chill requirement of 650 hours.
'Rio Grande' ripens in early June with large, 2 to 2 1/4 inch (105 grams) peaches. Fruit are round with a tip, yellow fleshed with a 60% red blush and freestone. 'Rio'-Grande' has good firmness and flavor and is recommended for planting on Iwarm sites in north Florida having a chill requirement of 450 hours.
'Suwannee' ripens in mid June and should end the commercial season. Fruit are medium size, 1 7/8 to 2 inch diameter (75 grams) and freestone. Fruit have a 60% red blush, yellow flesh, round with a suture with good firmness and excellant flavor. 'Suwannee' is recommended for planting in north Florida with a chill requirement of 650 hours.
'Harvester' ripens in mid June with 'Suwannee'. Fruit are medium size, 2 inch diameter (85 grams), yellow flesh and freestone. Fruit have a 70% red blush, good firmness and flavor. 'Harvester' is recommended for trial planting only with a marginal chill requirement of 750 hours.
Peach varieties included in this evaluation but currently not recommended for north Florida are 'Springold', 'Bicentennial', 'Sunnyside', 'Fairway', and 'Loring'. Although 'Springold' is an early ripening cultivar, its chill requirement of 850 hours is considered high for north Florida. 'Bicentennial' also ripens early in the season but fruit size has been small and it has a marginal chill requirement. Both 'Sunnyside' and 'Fairway' are susceptible to bacterial leaf spot and should not be planted where this disease is a problem. Because of the late ripening period and marginal chill requirement, 'Loring' is not recommended for commercial planting in north Florida.

Nectarine Variety Recommendations

Figure 2 shows the order and time of ripening of five nectarine varieties. 'Arming' is the first nectarine to ripen in early May while 'Sungold' ends the season in late June.
'Arming' ripens in early May with large 2 to 2 1/4 inch diameter (100 grams) fruit. Fruit have an 80% red exterior, yellow flesh and clingstone. 'Aming' has only average flavor but earliness and size more than compensate for lack of quality. 'Arming' requires 600 hours of chilling and is recommended for north Florida.
'Arm ueen' ripens in mid-May, with small to medium size fruit, 1 7/8 inch
diameter (67 grams). Fruit are yellow fleshed, round with a suture and have good firmness and flavor. 'ArmQueen' is recommended for trial planting in north Florida with a chill requirement of 650 hours but should be thinned early and heavy,
'Sunlitel ripens in mid to late May with round medium size fruit, 1 7/8
inch diameter (70 grams). Fruit have yellow flesh, 60% red blush and freestone. 'Sunlite' has medium firmness and good flavor and is recommended for planting on warm sites having a chill requirement of 450 hours,
Nectarine varieties included in this evaluation but currently not recoinmended for commerical production in north Florida are 'Sunrich' and 'Sungold'. In recent years, they have not competed favorably with California nectarines. 'Sunrich' and 'Sungold' are still recommended for homeowner and pick-your-own operations.








Figure 1. Normal ripening sequence of peach Agricultural Research Center, Monticello,


Figure 2, Normal at Agricultural


ripening Research


cultivars at


sequence of nectarine cultivars Center, Monticello,


April May June
1 10 20 1 10 20 1 10 20

Camden
Springold Springbrite Springcrest Bicentennial Flordaking June Gold Maygold Sunnyside Fairway Rio Grande Suwannee Harvester Lorino


May June
10 20 1 10 20

ArmKing
ArmQueen
Sunlite
Sunrich Sungold


%. a






0




Full Text

PAGE 1

AGRICULTURAL RESEARCH CENTER MONTICELLO Monticello, Florida Monticello ARC Research Report 1978-3 JUN O s ci -/.::,/ l:3 TRIAL INSECT MANAGEMENT SYSTEM FOR PECANS L I.F. A. S. _ lJ ,, . . ! J c B 11 L A H 1 d T E C k l --.rn ,-.._ n 1 . 1 ' 0 f f/ o ,. , ,., ' . . a , . . a sey an . . roe er ----..:__ . , u a J -.....,__, ... ~--.J Rationale for Pest Management Prior to the late 1940 1 s the number and effectiveness of pesticides avail able to growers was limited. Because of this, treatments were keyed to the life cycle of the insects and their most vulnerable stage or period. The advent of the "modern" organic pesticides, however, seemingly freed the grower from such constraints on timing. The new chemicals such as DDT, dieldrin, parathion, etc. were so effective and had such broad spectrum of activity that growers could apply them at protracted intervals and still achieve unheard of control. In this manner, timing for the pest became less important (critical) and it was expedient to schedule sprays by the calendar to facilitate planning and efficiency of the farm operation. Unfortunately, this ideal situation was not to last, terminated by the natural resilience of biological systems. Pests developed resistance to the chemicals and others, not previously important, became pests when their natural enemies were killed by the pesticides. In response, growers began applying pesticides at shorter intervals and higher rates. Resistance and secondary pest outbreaks were hastened while costs increased and control decreased . In a way we have come full circle. Because of increasing costs through factors mentioned above, we once more must match treatments to the life cycle of the pest and ideally only when the cost of treatment is justified by a greater loss from damage. Preliminary trials in Alabama and Georgia on managing insect pests in pecans, basing treatments on pest levels rather than calendar inter vals, have shown a reduction in spray cost without reduction in yield or quality. Presently, we do not have economic thresholds for the pecan insects, because information is lacking on the amount of damage done. The treatment levels suggested are designed to give a large margin of safety. For the most part, levels and sample size have been extracted from the Alabama and Georgia programs. As our experience increases and more information is gathered, these levels will probably be revised upward. Brief Biology of Major Pests Pecan Nut Casebearer: The nut casebearers overwinter as small larvae in cocoons attached to buds of the pecan tree. In late winter and early spring the larvae leave their cocoons and feed on buds and developing shoots. Adult moths from this generation emerge in late April and May and egg laying coin cides with the time that young nuts first appear. The small flat eggs are laid on the nuts near the blossom end < and upon hatching the larvae will feed on buds 1 Assistant Entomologist (ARC, Monticello), county :. Extension Director (Jefferson County)~ and Associate '. Extension Horticulturist (Fruit Crops Department Gainesville), respectively.

PAGE 2

before entering the nuts. Generally, only one egg is laid per cluster. This is the most destructive generation because a single casebearer larva can destroy several nuts or even the entire cluster. In later generations the nuts are large enough so that a larva will complete its development in a single nut and treatment is seldom required. The larvae (worms) are dark gray with a black head~ Damage is characteristic and easily recognized because of the mass of borings and excrement held together on the outside of the nut by a loose mat of silk. Yellow Aphids: Yellow pecan aphids overwinter as eggs on the bark of the pecan tree. Eggs hatch in the spring and the nymphs moveonto the foliage. As the name implies, nymphs and adults are yellow in color. The youngest nymphs are extremely small and easily overlooked. Feeding is confined to the leaves and almost exclusively to the lower surface. Development is rapid and there are many generations a year. There appear to be two population peaks a year: one in late spring and early summer, another in late summer or fall. The actual effect of yellow aphid feeding is unclear, but it does appear that heavy populations can reduce nut size and quality. These aphids produce copious amounts of honeydew, which, if not washed off by rains, support the growth of a black, sooty-mold fungus. Sooty-mold does not harm the plant directly, but by blocking light coming to the leaves, it reduces the plant's ability to manufacture nutrients. Hickory Shuckworm: The hickory shuckworm is principally a pest of the more mature nut. Shuckworms overwinter as larvae and pupae in old shucks on the ground and in the trees. Adult moths emerge in late winter and early spring before there are nuts on the pecan trees. These adults fly to hickory and their larvae . feed in the hickory nuts and phylloxera galls. Adults from this genera tion move back to pecans. Larvae feed inside developing nuts and in the shuck after the shell has hardened. Generally, larvae destroy few nuts in June, but in mid summer heavy nut loss can occur. Before shell hardening, attacked nuts drop from the trees. After the shell has hardened, feeding is confined to the shuck which may result in poor kernel development and adhesion of the shuck, which blackens the shell and makes removal difficult. Black Aphid: The black pecan aphid, although present on the foliage throughout most of the growing season, generally does not build up to damaging levels until late summer and fall. Black aphids apparently secrete a toxin that causes a yellow spot around the feeding site which gradually enlarg~s and eventually turns brown. Enough spots will cause the leaf1et to drop. Because of the time of occurrence, the consequence of defoliation caused by black aphids is greatest on the next year's crop, precluding adequate nutrient storage for nut set. Like the yellow aphids, the youngest stage of the black aphid is barely visible to the naked eye, considerably smaller than a pin head. The nymphs are greenish brown and the adults are dark with prominent black tubercles. Black aphids do not form large colonies but are found scattered on both upper and lower leaf surface. Pecan Weevil: Adult pecan weevils emerge from the soil in late summer through fall in north Florida. Adults feed on the nuts, but eggs are not laid until the shell has hardened and the kernel tissue begins to solidify. One to several eggs will be laid in a single nut. The white, grub-like larvae feed exclusively on the nut kernel. When the larvae have reached full development, they chew a circular hole through the shell and enter the soil. Normally, these larvae remain inactive in the soil until the second year when they change to adults and the cycle starts again.

PAGE 3

Sampling Program and Treatment Levels. Time Pest Species Sample Size 1 Treatment Level April July 1 Nut Casebearer 20 clusters per tree 2 Eggs found on 5 % Yell ow Aphid 5-10 % of trees in of clusters. small orchard. Treat when majority of eggs in red ring stage. Blacklight trap 2 lights per orchard. 10 compo~nd leaves per tree. Helps time egg sample and treatment. 4 moths per night. 30 aphids per com pound leaf. July 1 October Hickory Shuckworm Blacklight trap 2 traps per orchard. 6 moths per night per trap. 1 Yellow Aphid Black Aphid Pecan Weevil 10 compound leaves per tree. 10 compou~d leaves per tree. 10 aphids per leaf. 1 aphid per leaf. Screen cages, burlap When weevils present bands~sticky and shells have bands?. hardened. Pecan cultivar and location in the orchard can effect the levels of a particular pest species. Therefore sampling should take this into consideration. Divide the orchard into quadrants and sample an equal number of trees from each quadrant. Sample each variety, if possible, in proportion to their numbers in the orchard. Mark the trees with flagging or other easily seen material at the beginning of the season and sample the same trees throughout. Sampling should be conducted twice a week. 2 Completely circle tree, randomly selecting clusters that can be reached from the ground. Clusters can be examined without removing from the tree. 3 Circle tree, randomly selecting leaves. Inspect low~r leaf surface taking care not to dislodge aphids. 4 Circle tree, randomly selecting leaves. Examine both upper and lower leaf surface. 5 To be done only in orchards known to have weevil problems. For weevil sampling, select trees that have had heavy infestations. The grower should choose the sampling technique that is easiest for him to work with see "Sampling Adult Pecan Weevils" by W. W. Neel and M. Shepard. S. Coop. Ser. Bul. 208. 1976. (Spray materials and rates can be found in: "Pecan Insect and Disease Recommen dations" by J.C. Ball and W. J. French. ARC, Monticello Res. Rept. BB1978-2.)

PAGE 4

--------! ' , , -•

PAGE 5

AGRICULTURAL RESEARCH CENTER MONTICELLO Monticello, Florida Monticello ARC Research Report 1978-4 July 26, 1978 COMMERCIAL PEACH AND NECTARINE VARIETY RECD 2 El'feJM~ LIBRARY_ C. P. Andrews and C. E, Arnoldl OCT 2 3 1978 Commerical peach production in north Florida would J.A PPPR..~ble without vanieties adaptable to our area. Peaches grown in nort ~fl!Vt!Qf /Ffor-itt volume shipments of the season. Yet, the number one problem affect1n industry is the lack of better adapted varieties. Peach and nectarine cultivars currently recommended for north Florida range in chill requirements from 450 to 750 hours below 450F (7C). Another factor influencing this industry is the earliness of fruit ripening. For maximum profits, peach and nectarine varieties should ripen before those grown in the large production areas of Georgia, South Carolina and California while fruit quality must be acceptable on northern commeri cal markets. . Peach Variety Reconmendations Figure 1 illustrates the order and time of ripening of 14 peach varieties in a normal season. 1 Carr-den 1 starts the season the last week in April while 1 Loring 1 is the last cultivar ripening in mid to late June. 'Camden' ripens in late April but fruit size has been small, averaging 1 3/4 inches in diamet~r or 55 grams. Fruit are yellow fleshed with a 60% exterior red blush. Fruit ~re round with a prominent suture, clingstone with good firm ness and average flavor. 1 Camden 1 is recommended for trial or limited plantings only. Its chill requirement of 750 hours is considered marginal for north Florida. Fruit should be thinned early and heavy. 1 Springbrite 1 ripens in early May. Fruit size has been small to medium, 1 3/4 to 1 7/8 inch diameter (70 g.) with early and heavy thinning. Fruit are attractive, having an 80% red blush, yellow flesh, round with a suture and tip and sernifree. It is recommended for north Florida having a chill requirement of 650 hours but should be thinned properly. 1 Springcrest 1 ripens in early May but fruit size has been small, 1 3/4 inch diameter or 57 grams. Fruit have a 70% red blush, yellow fl~sh, round with a tip and clingstone. 1 Springcrest 1 has good firmness with average flavor. Quality of many early varieties is not as high as those ripening later in the season. 1 Springcrest 1 (700 hours) is recommended for trial planting but should be thinned early and heavy to increase fruit size. 'Flordaking' ripens in early May with 1 Springcrest 1 Fruit are large, 2 to 2 1/4 inch diameter (100 ~rams). Fruit have a 70% light red blush, yellow flesh, round with a suture and clingstone. 1 Flordaking 1 should be planted on warm sites since its chill requirement is 450 hours. 1 Assistant Horticulturist and Associate Horticulturist. 2 This research report was prepared in collaboration with T. E. Crocker, Extension Horticulturist .

PAGE 6

' 'June Gold' ripens in mid-May and is the leading variety grown in Florida, Fruit are large, 2 to 2 1/4 inch diameter (105 grams), yellow fleshed and have a 60% red blush. Fruit are round with a tip and have good firmness and flavor. 1 June Gold' is recommended for north Florida with a chi 11 requirement of 650 hours . . . ~ . , ~ . , it . 'Maygold c ripens in late May with medium size fruit, 2 inch diameter (80 grams). Fruit are round with a tip, 50% red blush, yellow fleshed and clingstone, 'Maygold' is recommended for north Florida with a chill requirement of 650 hours. ' 'Rio Grande' ripens in early June with large, 2 to 2 1/4 inch (105 grams) peaches. Fruit are round with a tip, yellow fleshed with a 60% red blush and freestone ; , 1 Rio ~_ Grande 1 has good firmness and flavor and is recommended for planting on warm sites in north Florida having a chill requirement of 450 hours. 'Suwannee' ripens in mid June and should end the commercial season. Fruit are medium size, 1 7/8 to 2 inch diameter (75 grams) and freestone. Fruit have a 60% red blush, yellow flesh, round with a suture with good firmness and excel lant flavor. 'Suwannee' is recommended for planting in north Florida with a chill requirement of 650 hours. 'Harvester' ripens in mid June with 'Suwannee'. Fruit are medium size, 2 inch diameter (85 grams), yellow flesh and freestone. Fruit have a 70% red blush, good firmness and flavor. 'Harvester' is recommended for trial planting only with a marginal chill requirement of 750 hours. Peach varieties included in this evaluation but currently not recommended for north Florida are 'Springold', 'Bicentennial', 'Sunnyside', 'Fairway', and 'Loring'. Although 'Springold' is an early ripening cultivar, its chill require ment of 850 hours is considered high for north Florida. 'Bicentennial' also ripens early in the season but fruit size has been small and it has a marginal chill requirement. Both 'Sunnyside' and 'Fairway' are susceptible to bacterial leaf spot and should not be planted where this disease is a problem. Because of the late ripening period and marginal chill requirement, 'Loring' is not recommended for commercial planting in north Florida, Nectarine Variety Recommendations ... Figure 2 shows the order and time of ripening of five nectarine varieties. 'ArmKing' is the first nectarine to ripen in early May while 'Sungold' ends the season in late June. 'ArmKing' ripens in early May with large 2 to 2 1/4 inch diameter {100 grams) fruit. Fruit have an 80% red exterior, yellow flesh and clingstone. 'ArmKing' has only average flavor but earliness and size more than compensate for lack of quality. 'ArmKing' requires 600 hours of chilling and is recommended for north Florida. 'ArmQueen' ripens in mid-May, with small to medium size fruit, 1 7/8 inch diameter (67 grams). Fruit are yellow fleshed, round with a suture and have good firmness and flavor. 'ArmQueen' is recommended for trial planting in north Florida with a chill requirement of 650 hours but should be thinned early and heavy. 'Sunlite' ripens in mid to late May with round medium size fruit, 1 7/8 inch diameter (70 grams). Fruit have yellow flesh, 60% red blush and freestone, 'Sunlite' has medium firmness and good flavor and is recommended for planting on warm sites having a chill requirement of 450 hours, Nectarine varieties included in this evaluation but currently not recom~ ; mended for commerical production 1n north Florida are 'Sunrich' and 'Sungold'. In recent years, they have not competed favorably with California nectarines. 'Sunrich' and 'Sungold' are still recommended for homeowner and pick~your-own operations.

PAGE 7

. j Figure 1! Normal ripening sequence of peach cultivars at Agricultural Research Center, Monticello, April May June 1 10 20 1 10 20 1 10 20 Camden \ I Springold Springbrite Springe rest Bicentennial Flordaking June Gold Maygold Sunnyside Fairway Rio Grande Suwannee Harvester Loring Figure 2, Normal ripening sequence of nectarine cultivars at Agricultural Research Center, Monticello, May June 1 10 20 1 10 20 ArmKing ArmQueen Sunlite Sunrich Sungold

PAGE 8

L ,. . _ ...


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