Barnett, William W. : William W. Barnett is Area IPM Specialist, University of California Cooperative Extension, Fresno.

Lindegren, James E. : James E. Lindegren is Research Entomologist, Stored-Product Insects Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Fresno, California

to control Applying parasitic nematodes carpenterworms in fig orchards James E . Lindegren 0 William W . Barnett moderate temperatures ; availability of the insects inhabiting hidden environments that T h e carpenterworm ( CW ) is a native wood - total CW larval population for treatment ; are difficult to reach with conventional insec - boring insect pest found in commercial fig and easy identification of infested trees , be - ticides . varieties in the San Joaquin Valley and in The most effective temperatures for the cause frass accumulations areundisturbed by several native , ornamental and agriculturally nematodeâ??s searching activity range between harvest machinery . Since one surviving CW important trees throughout the United States 15.5 â?? and 32 â?쳌 C ( 60 â?? and90 â?? F ) . Temperatures female can reinfest the same tree , the goal is and Canada . Other trees infested in the San exceeding 32 â?? C are lethal to the nematode . to eliminate all CW larvae from each infested Joaquin Valley include almond , walnut , tree . Those below 15.5 â?? C and above freezing , al - pecan , loquat , oak , elm , willow , cotton - The following procedure is recommended though not harmful , restrict its searching ac - wood , and poplar . for the control of CW larvae in fig orchards . tivity and therefore its effectiveness . Carpenterworms , Prionoxystus robiniue Nematode suspensions can be applied to ( Peck ) , overwinter as partially to fully de - Application by oil can the galleries with backpack sprayers or oil veloped larvae deep in the heartwood of the Nematodes are applied with a 20 - ounce cans . The applicators in a 1981 field trial pre - tree . Larval activity may begin as early as ( 600 - ml ) oil can at a concentration of 25,000 ferred oil cans , because they were lighter and mid - March if the spring is unusually warm . invasive - stagenematodes per mlof thickened easier to manipulate inside the tree canopy . Moth emergence usually extends from mid - deionized ( DI ) or distilled water . The thick - The oil can was also more efficient , using April to June . Adults emerge in the evening , ening agent ( SGP 104 absorbent polymer , about half the nematode suspension required leaving behind a residual pupal skin pro - sold by Henkel Corporation , Minneapolis , with a backpack sprayer . An oil can with a truding from the gallery opening . The Minnesota ) is used at a rate of 1gram ( about 20 - ounce ( 600 - ml ) capacity contains enough females release a sex pheromone , which at - 1 / 4 level teaspoon ) per 400 ml ( about 1V3 cups ) nematodes to treat about 25 acres of fig trees tracts the strong - flying males . Mating occurs DI water to prevent the nematodes from set - at a 10 percent CW infestation level . soon after emergence , and the heavy - bodied tling . Tap water is not recommended , be - female deposits most of her 300 - plus eggs on Timing cause its mineral content may reduce the the tree from which she emerges . Eggs hatch thickening agentâ??s effectiveness . Nematode Nematodes can be successfully applied to 10 days later , and the larvae begin new gal - applications can be monitored for percentage the galleries anytime during larval activity , leries . of galleries actually treated by adding 1 to 2 from mid - April to early November , but fall Signs of carpenterworm activity in fig or - percent red or orange latex pigment ( 4 to 8 treatment is preferred , after figs have been chards ( California Agriculture , January - ml , or about ! hto 1 level teaspoonful , to 400 harvested . A problem with early spring appli - February 1981 ) are : gallery openings plugged ml DI water ) . cations is that cold weather reduces larval ac - with sawdust - like frass and , often , reddish Galleriesvary in sizeand will accept aslittle tivity , interfering with the identification of brown stains below the openings ; frass ac - as 0.3 ml to as much as 8.3 ml or more per ap - intested trees . CW pupae are susceptible to cumulations on the ground around the base plication . Applicators should be instructed to this nematode , but the gallery dries up during of the trees ; broken limbs with dark galleries apply the nematode suspension until it starts pupation . Dry , inactive galleries are difficult at the breaks ; stunted trees missing large to run out and to apply no more than two to locate and treat . A continuously emerging branches ; in the spring , residual pupal skins plungers full ( about 4 ml ) of nematode sus - adult population is also hard to control . protruding from gallery openings . pension per gallery . This method prevents Mid - May applications may be useful in Parasitic nematode over - application of the nematode concen - reducing the late - maturing portion of the trate and compensates for possible incom - CW population . These small galleriesmay be The â?? codling moth nematode , â?쳌 also re - plete delivery of the suspension as the oil can overlooked in fall treatment but are large and ferred to as â?? caterpillar nematode , â?쳌 Neoup - becomes empty . This procedure yields an easily found the following spring . Spring fo - lectuna curpocapsae Weiser , is beneficial average application rate of 2 ml per gallery . liage is also less dense , so that applicators can because it only parasitizes insects . It is harm - The oil - can nozzle should be insertedintothe move under the tree canopy and see the active less to plants and other animals . The nema - gallery opening before application to inject galleries more easily . tode has been found throughout the world , the nematodes as far as possible into the gal - If applications are made in July and Au - originally in parasitized codling moth larvae lery system . gust , the CW population is stable without associated with apple trees . This mobile bio - Application effectiveness can be moni - emerging adults , but new galleries are small logical control agent , which is easily reared tored by spraying the frass - plugged opening and hard to distinguish . Also , proper timing on insects or artificial media , can actively of each treated gallery ( identified by residual is necessaryto avoid high afternoon tempera - search for and parasitize the CW larva inside latex pigment ) one week after application tures and irrigation and harvest operations . its gallery . Consequently , the nematode pro - with a yellow or other bright - colored spray The advantages of fall applications are : vides a new approach for the control of such CALIFORNIA AGRICULTURE , NOVEMBER - DECEMBER 1982 7 Previously treated trees will be easier to iden - tify for nematode reapplications and moni - toring of CW larval activity if the base of the trunk is marked with paint during the first application . Rope caulking putty may be used to seal the galleries after the nematodes are applied , loss of nematode suspension preventing the and thereby increasing the effectiveness of the application . This technique , although time - consuming , may be used in a cleanup or in ongoing spot treat - third application ments either for CW eradication from the orchard or for continuous population sup - pression . CW larvae often open plugged galleries before succumbing to the nematode . These of galleriescan be monitored , without the use the paint spray , by smoothing the putty from the active galleries back over the openings one week after the application and reexam - _ _ Blue paint marks frass plug of treated galleries . If this plug remains intact a week later , the ining the pluggedgalleries for activity a week CW larva is presumed dead ; if plug is not intact , gallery must be re - treated . later . Other management concerns Dead trees and prunings should be re - moved from the fig orchard each year before CW emergence from dead March to prevent wood . If possible , susceptibletrees in residen - tial sites bordering treated orchards should be CW and treated if they are in - examined for fested . Treatment of such trees may help pre - vent CW reintroduction into the treated orchard . Application of the codling moth nematode for controlling CW larvae in San Joaquin Valley fig orchards represents the first com - mercially feasible use of this biological con - trol agent in the United States.The nematode , through the cooperative efforts of federal and state agencies and industry , has been ex - empted from EPA registration and is now available commercially . Fig growers can rear the nematodes , and have done so , on readily Nematodes are applied to a carpenterworm gallery at a concentration of 25,000 per ml with available bait crickets for orchard applica - a 20 - ounce oil can . Red latex dye identifies treated galleries for later monitoring . tions . paint . Larval activity can then be determined should require less time and fewer nema - Juiiies E . Lindegren is Reseurch Enioinologisi , a week later by checking to see if the previ - todes . Estimated cost of treating an acre of a Srored - Produci Insecis Research Luboruiory , ously sprayed frass plug is still intact . If the Black Mission fig orchard , 48 trees per acre , Agriculiurul Research Service , U.S . Depuriineni of gallery has not been reopened ( the frass plug at a 10 percent infestation rate , would be Agriculiure , Fresno , California , and William W . Burneii is Areu IPM Speciulisi , Universiiy of still covered with paint ) , the larva is pre - $ 10 for labor and materials , with re - about Culiâ??forniu Cooperuiive Exiension , Fresno . sumed dead . If the painted frass plug has treatment at about half the cost . This reseurcli wus supporied in purl by ihe Wes - been replaced with new frass , the larva is still tern Region IR - 4 , with inuiching extra project In a cooperative test conducted in the fall froin ihe USDA - ARS , Teinporurily Unus - funding of 1981 , the relatively untrained applicators active , and the gallery must be re - treated . signed Program Funds und u gruni froin ihe Culi - provided by the grower identified 93 percent forniu Fig Insiiiuie . Addiiionul labor wasprovided Re - treatment by Juck Lidell , Golden Srute Ranches , Fresno , CA , of the infested treesbut identified and treated und uddirionul neinuiodes by John Kirkpoirick , only 45 percent The percentage of infested trees identi - of the galleries . Their applica - B.R . Supply Co . , Exeier , CA . The uuihors also fied and treated depends on the ability and tions inactivated 85 percent of the treated gal - thank Dr . P . C . : Vuil , USDA - ARS , Roger Sineds , Golden Siure Runches , and Alicia and Murihu training of the applicator . Two or more appli - leries . Suure ; , U.C . Cooperative Exiension , for [ heir cations may be necessary . Subsequent appli - At least one reapplication should be made ussisiunce arid suggesiions in ihefield upplicaiioiis cations to previously identified infested trees of ihis neinuiode . two to three weeks after the first application . 8 CALIFORNIA AGRICULTURE , NOVEMBER - DECEMBER 1982