630 US ISSN 0271-9916 October 1988 RESEARCH EXTENSiON SERIES 097

Phytotoxicity of Insecticides and Acaricidesto Anthuriums

Trent Y. Hata and Arnold H. Hara

HlTAHR . COLLEGE OF TROPICAL AGRICULTURE Ai.~D HUMA..1~ RESOURCES . UNIVERSITY OF HAWAII

The Library of Congress has catalogued this serial publicationas follows:

Research extension series / Hawaii Institute of Tropical Agri­culture and Human Resources.-001--[Honolulu, Hawaii]:

The Institute, [1980-v. : ill. ; 22 cm

Irregular.Title from cover,Separately catalogued and classified in LC before and

including no. 044.ISSN 0271-9916 = Research extension series - Hawaii

Institute of Tropical Agriculture and Human Resources.1. Agriculture-Hawaii-Collected works. 2. Agricul­

ture-Research-Hawaii-Colletted works. 1. HawaiiInstitute of Tropical Agriculture and Human Resources.II Title: Research extension series - Hawaii Institute ofTropical Agriculture and Human ResourcesS52.5R47 630'.5-dcl9 85-645281

AACR 2 MARC-SLibrary of Congress [8506]

THE AUTRORS

Trent Y. Rata is a research associate. Beaumont Agricultural Research Center (Hilo), Hawaii Instituteof Tropical Agriculture and Human Resources, University of Hawaii at Manoa.

Arnold H. Hara is an associate entomologist, Beaumont Agricultural Research Center (Hilo), HawaiiInstitute of Tropical Agriculture and Human Resources, University of Hawaii at Manoa.

ACKNOWLEDGMENTS

The authors gratefully acknowledge A. Magno and E. Notley for technical assistance. and Green PointNurseries. Hawaiian Heart Inc.. and Sunshine Farms for their cooperation. This research wassupported by the State of Hawaii. Governor's Agriculture Coordinating Committee. Grant No. GACC85-5.

CONTENTSPage

Introduction 1Materials and Methods 1Results and Discussion 1Glossary 8References 8

PHYTOTOXICITY OF INSECTICIDES AND ACARICIDESTO ANTHURIUMS

Trent Y. Hata and Arnold H. Hara .

INTRODUCTIONInsecticides and acaricides are commonly

used on anthurium (Anthurium andraeanumAndre) to produce marketable flowers. Alimiting factor in using certain insecticides andacaricides on anthurium is phytotoxicity, orplant injuries resulting from pesticide applica­tions. Phytotoxic responses differ amonganthurium cultivars; an insecticide that is safeon one cultivar may not be safe on another.

Phytotoxic pesticides usually produce acharacteristic injury to anthurium cultivarsthat may affect the entire plant or only parts ofthe plant. Typical phytotoxic responses includechlorosis, necrosis, bronzing, mottling, ab­normal growth, and leaf drop.

The purpose of this study was to test certainregistered and experimental insecticides andacaricides for phytotoxicity to anthuriums.

MATERIALS AND METHODSTwenty insecticides and acaricides were

tested on various anthurium (Anthuriumandraeanum Lind. and Andre) cultivars betweenMarch 1986 and March 1987 in Hilo andMountain View, Hawaii. All anthuriums weregrown in volcanic cinder and under 80 percentpolypropylene net shade. Each test plotconsisted of 18 plants. Pesticides were tested atfour times the recommended rate and weresprayed at weekly intervals for a minimum offour weeks. Sprays were applied until runoffoccurred (about 250 gallons per acre), using acompressed-air sprayer with a No. 8004 Teejetnozzle (Spraying Systems Co., Wheaton, IL) at 40psi. Phytoxicity to flowers and buds and toleaves was evaluated weekly during theapplication period and for six weeks after thelast application.

RESULTS AND DISCUSSION

Phytotoxic SymptomsTable 1 lists the phytotoxic results of 20

insecticides and acaricides on 13 anthuriumcultivars. The following discussion describes thephytotoxic symptoms caused by the testedinsecticides and acaricides.

Durs ban. All formulations of Dursbantested- 4 Emulsifiable Concentrate (EC), 50Wettable Powder (WP), and 1.0 Microencap­sulated (ME)- were phytotoxic to certain

anthurium cultivars (see Table 1) and tesulted inchlorotic and necrotic injury to the matureleaves of the plant. Dursban 50 WP and DursbanME were the least phytotoxic to the cultivars;Dursban 4 EC was the most damaging. Figure 1shows characteristic phytotoxic symptomsresulting from Dursban application.

Vydate LiqUid. Anthurium cultivarssusceptible to Vydate L injury responded withmottled leaves and curled margins. Vydate L is asystemic insecticide; symptoms may appear fourto six weeks after an application (Figure 2).

Orthene 75 Soluble Powder. Bronzed abaxialsurfaces were a characteristic injury symptom.Whites and pastels were preViously reported asvery susceptible cultivars (Mau, 1982). LikeVydate L, Orthene 75 SP is a systemic insecti­cide, and symptoms took several weeks toappear (Figure 3).

Isotox Insect Killer. InjUry was characterizedby crooked stems or leaf and spathe deformitieswith bronzed abaxial surfaces. Isotox containsOrthene and Kelthane and is also translocatedsystemically. InjUry appeared three to six weeksafter application. Ozaki cultivar developedpurple spots on the spathe, presumably a resultof the spray droplets. These spots, however, wereunnoticeable within a few days (Figures 4 and 5).

Kelthane 1.6 EC. Within seven days ofapplication, Kelthane 1.6 EC consistentlydamaged flowers in a majority of the cultivarstested. Damage was confined to the spathe,which developed distinct necrotic areas.Application to Calypso cultivar caused purplespots on the spathe, resulting from the spraydroplets (Figure 6).

Vendex 4 Land Talstar 10 WP. Thesemiticides were nonphytotoxic: however, anobjectionable spray residue did occur at the 4xrate. When tested at the recommended use rate,both miticides left minor residues, which wereunnoticeable on the flowers.

Tempo 2 EC. Tempo 2 EC was safe on themajority of cultivars tested; however, MickeyMouse cultivar developed a white spottedappearance on the underSides of the leaves(Figure 7).

Studies showed that there is variation in thetime period between application and manifesta­tion of injury. InjUry symptoms from contactinsecticides appeared more qUickly than thosefrom systemic insecticides. Phytotoxic contact

1

Table 1. Phytotoxicity of certain insecticides and acarlcides to various anthurium cultivars at 4x therecommended rate

Treatment and rate/ 100 gal 021 NI CA KA HB KZ MS OS MI SE AN MK KO

Avid 0.15 EC. 2.0 pt S2 S S S S S S S S S S S SCygon 400 EC.3 4.0 pt S S S S S S S SDanitol2.4 EC.4 21.2 fl oz S S S S S S S S S S S S SDimethoate 267 EC.s 6.0 pt S S S S S S S S S SDursban 4 EC. 4.0 pt S U S S U U L S S U SDursban 50 wp. 4.0 lb S U S S M U L S S S SDursban 1.0 ME.3 16.0 pt S M S M S M S S M S S M SIsotox Insect Killer, 37.5 pt S S S S S S U U MKelthane 1.6 EC.3 4.0 pt U U L U U U S U ULannate L.s 8.0 pt S S S S S S S S S S SMalathion 5 EC. 8.0 pt S S S S S S S S S SMavrik Aquaflow 2.0 F,

1.25 pt S S S S S S S S S SMetasystox R 2 EC 6.0 pt S S S S S S S S SOrthene 75 SP. 42.0 oz S S S S S S UPentac Aquaflow 4.0 F.3

32.0 fl oz S S S S S S S SSavey 50 WP.4 8.0 OZ S S S S S S S STalstar 10 WP.6 4.0 lb S S S S S S S S S S STempo 2 EG. 8.0 fl oz S S S S S S S S L S S S SVendex 4 L , 4.0 pt S S S S S S S S SVydate L.3 16.0 pt S U M U S U U S

lCultivar abbreviations: 02 = Ozaki, NI = Nitta, CA = Calypso, KA = Kaumana, HB = Hawaiian Butterfly, KZ = Kozohara, MS =Marian Seefurth, OS = Oshiro White, MI = Mickey Mouse, SE = Seapearl, AN = Anuenue, MK = Mauna Kea, KO = KobayashiObake.

2Relative safety: S = safe, M = moderate phytotoxicity, L = low phytotoxicity, U = unsafe.3Not registered for use on anthuriums. .4Experimental insecticide or acaricide.5Lannate Land Dimethoate 267 are registered under a special local needs (SLN) registration.6For greenhouse use only.

insecticides directly damaged flowers. buds. andleaves. while most phytotoxic systemicinsecticides caused injury to the primordia.which produced observable damage only toflowers and leaves that emerged several weeksafter the application.

Other FactorsMany other factors affect phytotoxicity.

Under certain conditions. pesticides that werereported safe in this report may be phytotOXic.The following are some of the more importantfactors that influence phytotoxicity.

Stressed plants. Insecticides should not beapplied to plants that are stressed. Plants thatare wilting are extremely sensitive to sprayinjury.

Temperature. Avoid spraying underextremely hot, sunny conditions (above gO°F).

2

Spray during the early morning or lateafternoon. when temperatures are cooler.

Formulations. Generally speaking. wettablepowders are considered safer for plants thanemulsifiable concentrate sprays. The latter typecontains emulsifiers and solvents that candamage plants. However, the disadvantage ofwettable powders is the white residue on thefoliage. a problem with ornamentals.

Adjuvants. These are substances added to thespray tank to improve the physical andchemical characteristics of the pesticide spray.Adj uvants are most commonly used to improvewetting. sticking, or spreading. These adjuvantscan sometimes cause injury to plants. Careshould be taken in selecting adjuvants and inadding the recommended amount to the spraytank.

Spray-tank mixtures. Mixing differentpesticides in the tank may result in plant injury

Figure 1. Dursban injUJY. Phytotoxic injwy first appears as chlorotic leaves (left}. In severe cases necrotic areas develop {right).

3

Figure 2. Vydate injury on Nitta cultivar. The first indication of phytotoxicity appears with the new emerging leaves (top). Leavesappear mottled and defonned at maturity (bottom).

4

Figure 3. Orthene Injury. Bronzed abaxial surfaces are a characteristic lDJury symptom.

5

Figure 4. Isotox injury on Seapearl cultivar: nower injury (right) and leaf injury (left). Bronzed abaxial surfaces and curledmargins are characteristic injwy symptoms. Leaves and flowers also m.ay become necrotic.

6

Figure 5. IsotoK injury on Anuenuc cuItivar. Abma1swfaces appear bronze:.

Figure 6. Kclt.lume injury on Kobayashi cultivur. Damage is confined to the spathe. which develops distinct necrotic areas.

7

Fi~e 7. Tempo 2 Be was safe 011 the ms,Jority of antburiumcultivars tested; however, white spots appeared 011 theundersides oC leaves 011 Mickey Mouse cultivar.

that would not occur if each pesticide wereapplied separately. Before pesticides are tankmixed, a compatibility chari should be con­sulted. Wettable powders should be mixed withother wettable powders and emulsifiable con­centrales with other emulsifiable concentrates.Plant injury also may occur when equipmentpreviously used for herbicides is used to applyinsecticides.

Each grower has unique conditions. It ishIghly recommended that the grower first testthe pestiCide on a small group of plants beforetreating the entire crop. Two to three applica­tions should be made at five- to seven-dayintervals, allowing two to three weeks after thelast application to observe for phytotoxiCity.When testing syslemic insecticides, the waitingperiod should be extended four to six weeks.

Use pesticides safely. Follow the manu­facturer's instructions on the use andapplication as well as storage and disposal. Thispublication is for educational purposes only.Consult your Cooperative Extension Service orthe Hawaii Department of Agriculture forauthorized special local need registraUons oradditional information.

NecrosisPesticide

CurlInsecticideLeaf dropMottle

AcaricideBronzing

8

GLOSSARYA substance lhat kills mites.Coppery bronze coloration of theleaves.

Chlorosis YelloWing, usually caused by sub­normal development of chlorophylLAbnormal bending or curling ofJeaves.A substance that kills insects.Premature falling of leaves.Variegated pattern of light and darkareas with di1Iused borders.Death of cells and tissues.A generic tenn for any substance usedto control any pest.

Phytotoxic insecticides lnsecticldes that causeinjury to plants.

Phytotoxicity The abUity of a substance to injurethe plant.

Special local need (SLN) registration A speCialstate registration given to peslicides foruse on specific local crops or slles notlisted on the pesticide product labeL

REFERENCESHara. A H., and R F. L. Mau. 1987. Guide for chemlcaJ

control of Jnsect and mite pests of anthutiurns.Cooperative Extension Service, Dept. of Entomol­ogy. University of Hawaii. HITAI-IR Brief 008.

Hara. A. H., R F. L. Mau. R. A Ctiley, and M. K. Wong.1983. Phytotoxicity of Insecticides and miticides toornamental plants. Proc. First Fertilizer &Ornamentals Workshop. University of Hawaii.HITAHR Research Extension Series 037:97-101.

Mau, R. F. L. 1982. Evaluation and registration ofinsecticides and milicides on anthurlum. Finalreport to the State of Hawaii. Governor'sAgriculture Coordinating Committee.

Reference to a company or product name does not imply approval or recommendation of the productby the College of Tropical Agriculture and Human Resources. University of Hawaii. or the UnitedStates Department of Agriculture to the exclusion of others that may be suitable.

Hawaii Agricultural Experiment StationHITAHR, College of Tropical Agriculture and Human Resources, University of Hawaii at ManoaNoel P. Kefford, Director and Dean

RESEARCH EXTENSION SERIES 097-10/88(2.3M)