![]() |
B-5041 |
Jerral D. Johnson, George Philley, James V. Robinson and George Ray
McEachern
Associate Department Head, Professor and Extension Program Leader for Plant
Pathology; Professor and Extension Plant Pathologist; Professor and Extension
Entomologist; and Professor and Extension Horticulturist; The Texas A&M University
System.
This guide provides information on insect and disease problems of peaches, plums, nectarines and pecans.
Homeowners should be familiar with insect pests and diseases, their life cycles and damage. Problems must be identified and proper control methods selected. The situation is often complex because problems vary from one area of Texas to another and from one year to the next. It is important to keep records of pest and disease occurrence to assist in making control decisions such as the timing of pesticide applications.
Plant diseases are most severe during periods of frequent rain or dew and mild temperatures (75 to 85 degrees F). Early-maturing peach varieties are more likely to have brown rot than late-maturing varieties, but late varieties are often damaged more by peach scab.
Healthy plants are more able to survive some insect and disease damage than plants already stressed by cultural problems. Optimum tree growth is maintained by following a well-balanced fertility program, selecting adapted disease-resistant varieties, and irrigating and pruning as needed.
Clean-up and residue disposal are important in reducing plum curculio, hickory shuckworm, brown rot of peach and pecan scab. Diseased material that is properly composted can be recycled as mulch or organic material.
Before using any pesticide, carefully read all instructions on the container. Follow instructions such as the need to wear protective clothing during mixing or spraying. Take necessary precautions when applying pesticides to avoid chemical exposure.
Mix pesticides in a well-ventilated area or outdoors. Avoid chemical contact with the skin and do not breathe chemical vapors.
Apply pesticides at the proper rate. Using less chemical then prescribed may result in poor control, while using more than recommended may result in excessive residue on the fruit or in plant damage.
Store chemicals in a secure area away from pets and children. Prepare only the amount required for one application. Properly dispose of any unused, diluted sprays and empty pesticide containers. Store pesticides in original containers.
A number of different sprayers can be used to apply insecticides and fungicides.
Compressed air sprayers range in size from 1 to 10 gallons; because of cost and handling ease, most homeowners prefer the 2 1/2- to 3-gallon sizes. Hose-on sprayers are less expensive but require a high volume of water, moderate pressure and a convenient water outlet. Applying wettable powders with a hose-on sprayer is difficult.
Once a sprayer has been used, it is considered a used pesticide container and requires proper handling and storage. Proper cleaning prolongs its life. Do not apply insecticides and fungicides with a sprayer previously used to apply herbicides; this may cause plant damage.
| Suggested pesticides are registered and labeled for use by the Environmental Protection Agency and the Texas Department of Agriculture. The status of pesticide label clearances is subject to change, and may have changed since this publication was printed. County Extension agents and appropriate specialists are advised of changes as they occur. | The USER always is responsible for the effects of pesticide residues on
livestock and crops, as well as for problems that arise from drift or movement of the
pesticide from ones property to that of others. ALWAYS READ AND CAREFULLY FOLLOW THE INSTRUCTIONS ON THE CONTAINER LABEL. |
For further information, contact your county Extension agent.
Table. 1 Homeowners spray schedule for pecans.
| Timing | Pest | Pesticide | Rate/ | Remarks |
| 1 gal. | ||||
| water1 | ||||
| Dormant season (winter) | Insects | |||
| Scale insects, | 97% oil | 1/4 - 1/3 pt. | Spray tree trunks and branches | |
| phylloxera | emulsion | thoroughly. | ||
| Budbreak (just as the buds | Nutritional | |||
| begin to split and show | Rosette | Zinc sulfate | 2 tsps. | Zinc sprays are essential for early |
| green color)--terminal bud | WP | season pecan growth. Early, frequent | ||
| growth should be 2 inches | or | applications will give the best | ||
| in length. | Zinc nitrate | response. Elemental zinc is toxic to | ||
| (NZN) liquid | most plants other than pecans and | |||
| grapes; therefore, avoid drift. If drift is | ||||
| a possibility, do not use zinc sulfate | ||||
| near peaches, plums, nectarines, | ||||
| apricots or other zinc-sensitive plants. | ||||
| Do not use any zinc product at higher | ||||
| than labeled rates since foliage burn | ||||
| can result. When applying more than | ||||
| one zinc spray in 2 weeks, reduce | ||||
| rate by one-half. Never spray young | ||||
| trees that are not actively growing. | ||||
| Insects | ||||
| Phylloxera | Malathion | 2 tsps. | If dormant oil was not used, then | |
| 50% EC | treat trees where a history of | |||
| (several | phylloxera damage indicates a need | |||
| formulations) | for control. | |||
| Budbreak | Diseases | |||
| Scab and | Benomyl | 1/2 - 1 Tbs. | ||
| other foliage | (Benlate | |||
| and nut | 50%WP) | |||
| diseases | or | |||
| Thiophanate- | 1/2 - 1 Tbs. | |||
| methyl (Topsin- | ||||
| M® 70% WP) |
1Due to variation in the concentration of pesticides in different products, refer to the label for the specific rate per 1 gallon spray solution.
WP = wettable powder
EC = emulsifiable concentrate
DF = dry flowable
CORRECTION The following is a correction to Extension Publication B-5041 "Homeowner's Fruit & Nut Spray Schedule." Diazinon 25% EC is no longer approved for use on pecans. Ciba Crop Protection, th emanufacturer of the product, voluntarily withdrew the use of diazinon on pecans as of August 31, 1995. their decision, according to company spokesmen, was based on the limited market opportunity for the product on pecans and not its safety. It should be noted that here may be containers of the product on store shelves or in homeowner inventory that have the older label attached. Product with the older label may be used safely and legally on pecans as long as the label directions are followed. |
Table. 1 Homeowners spray schedule for pecans (continued).
Timing |
Pest | Pesticide | Rate/ | Remarks |
| 1 gal. | ||||
| water1 | ||||
| Prepollination (when leaves | Nutritional | |||
| are one-third grown and | Rosette | Same as for | ||
| before pollen is shed)-- | budbreak | |||
| mid-April | ||||
| Diseases | ||||
| Scab and | Same as for | |||
| other foliage | budbreak | |||
| and nut | ||||
| diseases | ||||
| Insects | ||||
| Fall webworm | Bacillus | Refer to | Repeat sprays as pest problem recurs. | |
| thuringiensis | label. | |||
| Walnut | (several | |||
| caterpillar | formulations) | |||
| or | ||||
| Diazinon® 25% | Refer to | |||
| EC (several | label. | |||
| formulations) | ||||
| or | ||||
| Malathion® 50% | 2 tsps. | |||
| EC (several | ||||
| formulations) | ||||
| or | ||||
| Carbaryl | Refer to | |||
| (Sevin® liquid, | label. | |||
| several | ||||
| formulations) | ||||
| Pollination (when case- | Nutritional | |||
| bearer eggs appear on | Rosette | Same as for | ||
| tips of nutlets)--May | budbreak | |||
| Insects | ||||
| Pecan nut | Same as for | Apply during egg hatch. (Consult your | ||
| casebearer | prepollination | county Extension agent for precise | ||
| local timing.) | ||||
| Diseases | ||||
| Scab and | Same as for | |||
| other foliage | budbreak | |||
| and nut | ||||
| diseases |
1Due to variation in the concentration of pesticides in different products, refer to the label for the specific rate per 1 gallon spray solution.
WP = wettable powder
EC = emulsifiable concentrate
DF = dry flowable
Table. 1 Homeowners spray schedule for pecans (continued).
| Timing | Pest | Pesticide | Rate/ | Remarks |
| 1 gal. | ||||
| water1 | ||||
| Second generation | Insects | |||
| casebearer (42 days after | Pecan nut | Same as for | ||
| first casebearer spray) | casebearer | prepollination | ||
| Aphids | Diazinon® 25% | Refer to | Treat yellow aphids when an average | |
| EC (several | label. | of 25 per compound leaf are found | ||
| formulations) | or when excessive honey dew is | |||
| or | produced. Repeated use of insecti- | |||
| Malathion® | 2 tsps. | cides can result in strains of aphids | ||
| 50% EC | that are resistant to insecticides. | |||
| (several | This can result in increased losses. | |||
| formulations) | ||||
| or | ||||
| Cygon® 2 EC | Refer to | |||
| label. | ||||
| Diseases | ||||
| Scab and | Same as for | Additional sprays at 10- to 14- day | ||
| other foliage | budbreak | intervals may be required during | ||
| and nut | extended periods of rainfall or high | |||
| diseases | humidity. | |||
| Diseases | ||||
| Cover sprays | Scab | Same as for | Number of cover sprays is based | |
| budbreak | on weather conditions, variety and | |||
| presence of scab fungus. Maintain | ||||
| spray applications as long as weather | ||||
| conditions favor disease development. | ||||
| Water stage (when inside | Diseases | |||
| of the nut begins to fill | Scab and other | Same as for | Treat where there is a history of | |
| with liquid)-- mid- to late | foliage and nut | budbreak | disease or during periods of rainfall | |
| July | diseases | or dew. | ||
| Half-shell hardening | Insects | |||
| --mid- to late August | Aphids | Same as for | Treat yellow aphids when an average | |
| aphids listed | of 25 per compound leaf are found | |||
| above | or when excessive honeydew is | |||
| produced and aphid populations persist | ||||
| Hickory | Diazinon® 25% | Refer to | ||
| shuckworm | EC | label. | ||
| or | ||||
| Carbaryl | Refer to | |||
| (Sevin® liquid, | label. | |||
| several | ||||
| formulations) |
1Due to variation in the concentration of pesticides in different products, refer to the label for the specific rate per 1 gallon spray solution.
WP = wettable powder
EC = emulsifiable concentrate
DF = dry flowable
Table. 1 Homeowners spray schedule for pecan. (continued).
| Timing | Pest | Pesticide | Rate/ | Remarks | |
| 1 gal. | |||||
| water1 | |||||
| Half-shell hardening | Insects | ||||
| (continued) | Pecan weevil | Carbaryl | Refer to | Treat areas with | a history of pecan |
| (Sevin® liquid, | label. | weevil infestation. | One to three | ||
| several | treatments at | 10- to 14- day intervals | |||
| formulations) | are needed for | heavy weevil | |||
| infestations. | |||||
| Diseases | |||||
| Scab and other | Same as for | ||||
| foliage and | budbreak | ||||
| nut diseases |
Table 2. Homeowners spray schedule for peaches and plums.
| Timing | Pest | Pesticide | Rate/ | Remarks |
| 1 gal. | ||||
| water1 | ||||
| Dormant season | Insects | |||
| Scale insects | 97% dormant | 1/4 pt. | Apply when temperature is between | |
| oil | 40 and 70 degrees F. Use only once. | |||
| Apply only if scale are observed. | ||||
| Late dormant | Diseases | |||
| Peach leaf | Chlorothalonil | Refer to | Apply if fall applications of copper | |
| curl | (several | label for | fungicide were not made. | |
| formulations) | specific rate. | |||
| Petal-fall (when flower | Insects | |||
| petals begin to fall)-- | Plum | Malathion | 2 1/2 tsps. | Apply when 75 percent of petals |
| 5 days after bloom | curculio | 50% EC (several | have fallen, and there is a history of | |
| formulations) | insect damage. | |||
| or | ||||
| Cabaryl | Refer to | |||
| (Sevin® liquid, | label. | |||
| several | ||||
| formulations) | ||||
| or | ||||
| Peach twig | Diazinon® 25% | Refer to | The peach twig borer usually is a | |
| borer | EC (several | label. | problem only in the West Cross | |
| formulations) | Timbers area. | |||
| Lesser peach | Endosulfan | 2 Tbs. | Make two applications approximately | |
| tree borer | (Thiodan 9.7% | 3 weeks apart. Thoroughly wet tree | ||
| EC) | limbs with spray. |
1Due to variation in the concentration of pesticides in different products, refer to the label for the specific rate per 1 gallon spray solution.
WP = wettable powder
EC = emulsifiable concentrate
DF = dry flowable
Table 2. Homeowners spray schedule for peaches and plums (continued).
| Timing | Pest | Pesticide | Rate/ | Remarks |
| 1 gal. | ||||
| water1 | ||||
| Petal-fall (continued) | Diseases | |||
| Scab | Captan® 50% | 2.66 Tbs. | Treat where there is a history of | |
| WP | disease problems. | |||
| or | ||||
| Sulfur 97% WP | 8 Tbs. | |||
| or | ||||
| Benomyl | 1.5-2.25 Tbs. | |||
| (Benlate® 50% | ||||
| WP) | ||||
| or | ||||
| Thiophanate- | 1.5-2.25 Tbs. | |||
| methyl | ||||
| (Topsin-M® | ||||
| 70% WP) | ||||
| or | ||||
| Chlorothalonil | ||||
| (same as | ||||
| dormant) | ||||
| Shuck split (when the | Insects | |||
| calux separates from | Catfacing | Same | Treat where there is a history of cat- | |
| base of newly formed | insects, | insecticides as | facing insects and/or plum curculio. | |
| fruit)--14 days after bloom | plum | for petal fall | ||
| curculio | ||||
| Diseases | ||||
| Scab | Same | |||
| fungicides as | ||||
| for petal fall | ||||
| First cover (30 days | Insects | |||
| after bloom) | Catfacing | Same as for | ||
| insects, | petal fall | |||
| plum | ||||
| curculio | ||||
| Diseases | ||||
| Scab | Captan 50% | 2.7 Tbs. | Treat where there is a history of | |
| or | disease problems. | |||
| Sulfur 97% WP | 8 Tbs. | |||
| Cover sprays (repeat at | Insects | |||
| 14-day intervals) | Catfacing | Same | ||
| insects | insecticides as | |||
| for petal fall | ||||
| Diseases | ||||
| Brown rot | Captan 50% | 2.7 Tbs. | ||
| WP | ||||
| or | ||||
| Sulfur 97% WP | 8 Tbs. |
1Due to variation in the concentration of pesticides in different products, refer to the label for the specific rate per 1 gallon spray solution.
WP = wettable powder
EC = emulsifiable concentrate
DF = dry flowable
Table 2. Homeowners spray schedule for peaches and plums (continued).
| Timing | Pest | Pesticide | Rate/ | Remarks |
| 1 gal. | ||||
| water1 | ||||
| Pre-harvest | Insects | |||
| (For early-maturing varieties | June beetles | Carbaryl | Refer | |
| and during periods of | (Sevin® liquid, | to label. | ||
| frequent rain or dew--spray | several | |||
| 3 weeks, 2 weeks and 3 | formulations) | |||
| days prior to picking. For | ||||
| mid- to late-maturing | Diseases | |||
| varieties--spray at 2 weeks | Brown rot | Benomyl | 1.5-2.3 Tbs. | Do not apply within 3 days of |
| and at 3 days prior to | (Benlate®) | harvest. | ||
| picking.) | 50%DF | |||
| or | ||||
| Thiophanate- | 1.5 -2.3 Tbs. | Can be applied on day of harvest. | ||
| methyl (Topsin | Wash all of fruit before eating. | |||
| M® 80% WP) | ||||
| or | ||||
| Funginex® | Refer to | Not approved on plums in preharvest | ||
| (several | label. | period. | ||
| formulations) | ||||
| Post harvest--mid-to late | Insects | |||
| August | Peach tree | Chlorpyrifos | 2 Tbs. | Thoroughly wet from base of tree up |
| borer | (Lorsban® | to first scaffold limbs. | ||
| 12.9%) | ||||
| or | ||||
| Lindane | 1 Tbs. | |||
| (Lindane® 20% | ||||
| EC) | ||||
| or | ||||
| Endosulfan | 2 Tbs. | |||
| (Thiodan® 9.7% | ||||
| EC) | ||||
| Diseases | ||||
| Peach rust | Chlorothalonil | Refer to | Begin applications at first sign of rust | |
| label. | in the summer and continue at 2- to | |||
| 3-week intervals until early October. | ||||
| Rust is a problem in counties south | ||||
| of a line from Houston to Hallettsville | ||||
| and Rio Grande City. | ||||
| October 15 to December 1 | Diseases | |||
| Peach leaf | Copper | Refer to | Spray to run-off. Apply during | |
| curl | hydroxide | label. | dormant season. | |
| (several | ||||
| formulations) | ||||
| or | ||||
| Chlorothalonil | Refer to | |||
| (several | label. | |||
| formulations) |
1Due to variation in the concentration of pesticides in different products, refer to the label for the specific rate per 1 gallon spray solution.
WP = wettable powder
EC = emulsifiable concentrate
DF = dry flowable
Peaches, Plums, Nectarines, and Apricots - Use sulfur fungicides throughout the spray program. Decrease application interval to shortest interval allowed. Shortened intervals are important during the late bloom, shuck split and first cover period and again during the preharvest period. These are periods when fruit diseases are most damaging.
Pecans - Copper sulfate is considered an organic fungicide and some formulations are approved for use on pecans to control pecan scab and other foliage diseases. Copper sulfate is highly toxic to fruit trees such as peaches, plums, apricots and nectarines, and to some ornamental plants. Be careful when using this product around sensitive plants if there is a possibility of drift.
General Considerations - Most plant diseases require that the leaf, fruit or nut remain wet for a certain length of time for infection to occur. The following precautions should be taken to reduce the length of time the plant is wet following dew or rainfall: (1) prune trees to allow sunlight to penetrate the leaf canopy; (2) space trees to allow for air circulation; (3) plant trees in an area that will receive early morning sun and where air circulation will not be blocked by buildings or other plants; and (4) avoid wetting the tree during irrigation.
Select varieties that have natural resistance to the major diseases of your area. Resistance does not mean immunity to infections, but fungicide applications are usually more effective on plants with some resistance.
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.
Educational programs of the Texas Agricultural Extension Service are open to all people without regard to race, color, sex, disability, religion, age or national origin.
Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, and June 30, 1914, in cooperation with the United States Department of Agriculture. Zerle L. Carpenter, Director, Texas Agricultural Extension Service, The Texas A&M University System.
| 10M-5-96, Revision | PP, ENTO, HORT |