- Watermelon -

WATERMELON:  Citrullus lanatus (Thumb.),  ‘MickyLee’

GREENHOUSE BIOASSAYS WITH SYSTEMIC INSECTICIDES FOR CONTROLLING SQUASH BUG, 2000 

Squash bug (SB):  Anasa tristis (DeGeer)

            Watermelon seedlings grown in pots in a greenhouse at the Wes Watkins AREC, Lane, OK, were treated with systemic insecticides and then adult squash bugs were caged on plants to evaluate toxicity.  Seeds were planted in 23 cm diam pots filled to within 0.5 cm of the rim with a commercial potting soil media.  Pots were held in a greenhouse at approx. 28^o C.  When all seedlings had germinated and reached the one true-leaf stage the pots were treated with insecticides.  Formulated insecticides were mixed with water and 50 ml of each solution was poured and evenly distributed over the soil in the pots.  The experimental design was a CRD with 10 replicates of each treatment.  Two days after treatment, 30 cm tall cages with a 25 cm diameter were placed over pots and one female adult squash bug was placed in each cage and the top of the cage closed with mesh cloth.  Caged pots were monitored daily and number of dead squash bugs recorded.  Squash bugs were replaced at two day intervals.  Four replicate trials were conducted, each trial lasted from 10 to 12 days.  Data were subjected to ANOVA and means separated with a LSD test.

            Mortality of squash bugs was greatest on plants treated with Furadan and thiamethoxam.  Treatments with Admire and Vydate resulted in moderate levels of mortality.  Results indicate that soil applications of Furadan or thiamethoxam to seedling watermelon plants should provide excellent control of adult squash bugs for 10 to 12 days.

Table 1.

                        Mean no. dead squash bugs                             

Treatment / rates                         Trial 1                         Trial 2                         Trial 3                         Trial 4 

Furadan 4F / 0.5 ml/pot               0.93 a                         1.00 a                         0.90 a                         0.90 a 

Admire 2F / 0.4 ml/pot                0.06   c                       0  c                             0.60 b                         0.70  b

Vydate L / 0.4 ml/pot                  0.18 bc                       0.18 bc                          -                                 -         

thiamethoxam / 20 mg ai/pot           -                                -                               0.80 a                         0.90 a 

untreated                                    0.02  c                         0.13 bc                      0.02  c                         0.02  c

Numbers in a column followed by the same letter are not significantly different ( P=0.1; LSD)

‘-‘ indicates missing data

WATERMELON:  Citrullus lanatus (Thumb.),  ‘MickyLee’

GREENHOUSE BIOASSAYS OF SYSTEMIC INSECTICIDES TO CONTROL SQUASH BUG, 2001 

Squash bug (SB):  Anasa tristis (DeGeer)

            Watermelon seedlings grown in pots in a greenhouse at the Wes Watkins AREC, Lane, OK, were treated with systemic insecticides and then adult squash bugs were caged on plants to evaluate toxicity.  Seeds were planted in 23 cm diam pots filled to within 0.5 cm of the rim with a commercial potting soil media.  Pots were held in a greenhouse at approx. 28^o C.  When all seedlings had germinated and reached the one true-leaf stage the pots were treated with insecticides.  Formulated insecticides were mixed with water and 50 ml of each solution was poured and evenly distributed over the soil in the pots.  The experimental design was a CRD with 10 replicates of each treatment.  Two days after treatment, 30 cm tall cages with a 25 cm diameter were placed over pots and one female adult squash bug was placed in each cage and the top of the cage closed with mesh cloth.  Caged pots were monitored daily and number of dead squash bugs recorded.  Squash bugs were replaced at two day intervals.  Seven replicate trials were conducted, each trial lasted from six to 10 days.  Data were subjected to ANOVA and means separated with a LSD test.

Ten days after placing adult squash bugs on treated plants, there were significant levels of moratality for all of the treatments in comparison to the untreated plants.  Furadan treatments resulted in significantly more mortality than either Platinum or Neemix but not more than Admire.  Furadan treatments resulted in mortality levels of 90% or greater within 6 days after insects were placed on plants and this was significantly greater mortality than with any other treatment.  Results indicate that Furadan soil applications will result in greater mortality levels and in less time than will Admire, Platinum or Neemix.  However, the other insecticides will result in significant mortality of squash bugs.         
Table 1.

                        Mean no. dead squash bugs                             

Treatment / rates                         4 DAT                         6 DAT                         8 DAT                         10 DAT                

Furadan 4L / 0.4 ml/pot               0.67 a                         0.91 a                          0.93 a                          0.91 a

Admire 2F / 0.4 ml/pot                0.67 a                         0.69 b                          0.83 a                          0.82 ab

Platinum / 0.1 ml/pot                   0.46  b                         0.60  b                         0.57  b                         0.67  b

Neemix 4.5EC / 2.5 ml/pot        0.19  c                          0.28  c                         0.22  c                          0.33  c

untreated                                    0.02  d                         0.04  d                         0.03  d                          0.04  d

Numbers in a column followed by the same letter are not significantly different ( P=0.1; LSD)

DAT = Days after treatment

WATERMELON:  Citrullus lanatus (Thumb.),  ‘MickyLee’

CONTROLLING SQUASH BUG ON SEEDLINGS WITH CARBOFURAN SOIL INSECTICIDE APPLICATIONS, OKLAHOMA, 2002 

Squash bug (SB):  Anasa tristis (DeGeer)

Methods of applying carbofuran  to watermelon to protect seedlings from SB were evaluated by direct seeding and transplanting seedlings into bare soil and then treating seeds and transplants using varying methods of application of carbofuran.  The experimental design was a RCB with 8 treatments and 5 replicate blocks and the experiments were conducted at the Wes Watkins AREC, Lane, OK.  Plots were 10 ft long, 3-ft wide with 5-ft alleys between plots.  Seeds were planted in transplant trays in a greenhouse on 1 Jul.  Direct-seeded plots were treated prior to or at seeding on 22 Jul.  Transplants were treated at time of planting or immediately after planting on 22 Jul.  All treatments were made at the same rate (2.4 fl oz Furadan 4F / 1000 row ft).  Seed furrow treatments were made with a backpack sprayer calibrated to deliver a total volume of 20 gpa at 40 psi with a single hollow-cone nozzle directly over or in the seed furrow.  Drench applications were made with 1.1 qt of solution per  plot applied to the seed furrow or transplant row.  Applications to the foliage of transplants were made using the backpack sprayer at the same rate with the sprayer directed over the plants and row.  Bioassays for insecticide activity were conducted by collecting adult SB from a culture maintained in a lab at the AREC and holding them 24 hrs without food.  Two adult SB were then placed in cages over a seedling plant in each plot on 26 Jul and 2 Aug on transplants (2- leaf and 4-leaf growth stage) and on 8 and 18 Aug on direct seeded plants (2-leaf and 4-leaf growth stage).  After 48 hrs cages were removed and plants examined to determine number of dead SB.  Data were summarized and analysed using ANOVA and a means separation test to determine differences among treatments.

SB were not abundant in the field and no meaningful comparisons could be made among treatments and effects based on naturally occurring field populations.   Based on results of the caged insect bioassays, Furadan applied to the soil as a drench or over transplants provided significant levels of mortality of adult SB at the 2-leaf growth stage.  Furadan applied as a spray over transplants, injected to the side of the plants or as a drench resulted in significant mortality of SB at the 4-leaf growth stage.  In-furrow application of Furadan resulted in significant mortality of SB on direct seeded plants at the 2-leaf growth stage.  No other treatments resulted in significant levels of activity as judged by mortality of SB at the 2-leaf or 4-leaf growth stage.  Results indicate that any of the methods of application of Furadan should provide good control of SB when treating transplants.  However, none of the treatments resulted in significant activity when treatments were applied to direct seeded plantings.

Table 1.

                                                                                    % Mortality                             

Application method                             28 Jul                4 Aug          10 Aug          20 Aug

Direct Seeded                                     

In furrow @ planting                              -                       -               40 a                 0

Over furrow after planting                      -                       -               20 ab               20

Injected to the side @ planting               -                       -               30 ab               20

Untreated Seeded                                 -                       -                 0  b                  0

Transplants

Spray over plants                              100 a                60  b                -                       -

Drench after planting                         100 a               100 a                -                       -

Injected to side after planting              70 ab               90  a                -                       -

Untreated Transplant                          60 b                10  c                -                       -

% Mortality = (number dead SB / 2 SB per cage) * 100.

Means in a column followed by the same lower case letter are not significantly different (LSD, P=0.1).

WATERMELON:  Citrullus lanatus (Thumb.),  ‘MickyLee’     

CONTROLLING SQUASH BUG ON SEEDLINGS WITH CARBOFURAN SOIL INSECTICIDE APPLICATIONS, 2002 

Squash bug (SB):  Anasa tristis (DeGeer)

Methods of applying carbofuran  to watermelon to protect seedlings from SB were evaluated by direct seeding and transplanting seedlings into bare soil and then treating seeds and transplants using varying methods of application of carbofuran.  The experimental design was a RCB with 8 treatments and 5 replicate blocks and the experiments were conducted at the Wes Watkins AREC, Lane, OK.  Plots were 10 ft long, 3 ft wide with 5 ft alleys between plots.  Seeds were planted in transplant trays in a greenhouse on 1 Jul.  Direct-seeded plots were treated prior to or at seeding on 18 Jul.  Transplants were treated at time of planting or immediately after planting on 18 Jul.  All treatments were made at the same rate (2.4 fl oz Furadan 4F / 1000 row ft).  Seed furrow treatments were made with a backpack sprayer calibrated to deliver a total volume of 20 gpa at 40 psi with a single hollow-cone nozzle directly over or in the seed furrow.  Drench applications were made with 1.1 qt of solution per  plot applied to the seed furrow or transplant row.  Applications to the foliage of transplants were made using the backpack sprayer at the same rate with the sprayer directed over the plants and row.  Bioassays for insecticide activity were conducted by collecting adult SB from a culture maintained in a lab at the AREC and holding them 24 hrs without food.  Two adult SB were then placed in cages over a seedling plant in each plot on 30 Jul and 6 Aug on transplants (2- leaf and 5-leaf growth stage) and on and 21 and 28 Jul on direct seeded plants (2-leaf and 5-leaf growth stage).  After 48 hrs cages were removed and plants examined to determine number of dead SB.  Data were summarized and analysed using ANOVA and a means separation test to determine differences among treatments.

            The only treatment that resulted in significant mortality to SB adults on direct seeded plants was the over seed furrow application.  This treatment resulted in significant mortality for a period of 14 days after treatment and through the plant vining growth stage.   Applications of carbofuran over the transplant seedlings or to the transplant furrow resulted in significant levels of mortality for 14 days after treatment and through the plant vining growth stage.  Results indicate that application of carbofuran over the seed furrow or over plants or transplant furrows should provide control of adult squash bug at least through the plant vining stage of growth. 

Table 1.

                                                                                    % dead SB                              

Application method                         23 Jul               30 Jul            1 Aug               8 Aug

Direct Seeded                                     

In furrow @ planting                         -                       -               0.0  b               30 ab

Over furrow after planting                 -                       -               30 a                 50 a

Injected to the side @ planting          -                       -               10 ab               40 ab

Untreated Seeded                            -                       -                0.0  b               0.0  b

Transplants

Spray over plants                           100 a               90  a             -                        -

Drench after planting                      100 a             100 a              -                        -

Injected to side after planting          0.0 c               0.0  b             -                       -

Untreated Transplant                      20  b              0.0  b              -                      -

% dead SB = (number dead SB / 2 SB per cage) * 100.

Means in a column followed by the same lower case letter are not significantly different (LSD, P=0.1).

WATERMELON:  Citrullus lanatus (Thunb.)

Squash Bug: Anasa tristis (De Geer)

EFFICACY OF SOIL APPLIED INSECTICIDES FOR CONTROLLING INSECTS ON WATERMELON, OKLAHOMA, 2000.  This experiment was conducted at the Wes Watkins Agricultural Research and Extension Center, Lane, OK.  Plots for this experiment were measured and marked using a RCB design with 5 replicate blocks and 8 treatments and each plot measured 12 ft wide by 50 ft long with one row per plot.  Insecticides were applied to a 7-inch band over the seed furrow in the plots prior to planting with the exception of Warrior, which was applied as a foliar spray on June 18.  Watermelon, ‘MickyLee’, was direct seeded to the field on June 10.  Drip irrigation lines were placed in each plot.  Plots were examined at 7-day intervals and number of cucumber beetles, squash bugs, cutworms; number of leaves per plant and number of plants in 10-row ft were recorded.  Fruit yield in each plot was determined at maturation by counting and weighing all fruit in each plot.  Roots from 3 plants per plot were examined for insect feeding damage immediately after harvest.   Bioassays were conducted by caging adult squash bugs on individual plants during the first 2 weeks after germination.  Plants were thinned to 3 ft intervals after plants reached the 3-true leaf stage. 

Insect pests were virtually nonexistant in plots in the spring of 2000 and there were no significant differences in numbers of insects in plots treated with different insecticides.  Bioassays were conducted on 20 June and none of the treatments resulted in mortality of squash bugs caged on plants after 48 hours of exposure.  There were no significant differences in numbers of dead plants recorded in plots on any of the survey dates.  Counts of live plants at germination indicated no significant treatment affects except that the untreated plots had more plants than plots treated with thiamethoxam and lorsban.  One week after thinning germinated plants to a final stand density of 15  plants per plot there were no significant treatment affects.  Counts of number of leaves per plant when plants began to vine (5 Jul) indicated plants treated with a foliar application of Warrior had significantly more leaves than those in untreated plots.  There were no other significant treatment affects.  There were no significant fruit yield differences attributable to insecticide treatments.  There was no notable damage to plant roots examined after fruit was harvested.  In summary, there was little to no insect pest pressure in the spring of this year and the trials should be repeated for at least one more year.

Means in a column followed by the same letter are not significantly different, LSD, P=0.1.

Rates are expressed as material per 1000 row ft unless otherwise noted.

WATERMELON:  Citrullus lanatus (Thunb.)

Squash Bug; Anasa tristis (De Geer)        

            CONTROL OF SQUASH BUG IN A COMMERCIAL WATERMELON FIELD, 1998:  Watermelon plants were transplanted into beds in mid Apr.  The field was located near Terral, OK.   The experimental design was a RCB with 4 replicates and 7 treatments.  Plots were one row wide (72 inches) and 45 feet long.  Plots were treated with insecticides using a CO₂- powered bicycle type sprayer with a broadcast application of 72 inches from 4 conejet (TXVS26) nozzles applying 38 gpa at 40 psi.  Plots were treated on 24 Jun and 1 Jul.  Plots were surveyed to determine squash bug abundance on 1 and 7 Jul by visual examinations of  1/2-meter square areas in 3 locations in each plot and counting all insects present.

            Squash bugs were very abundant when treatments were initiated.  Metasystox R and Warrior significantly reduced populations of adults and nymphs in comparison to the untreated plots and plots receiving Provado and Neemix.  Provado and Neemix treated plots had more squash bugs than all other treatment plots and the untreated plots.  Results indicate that Metasystox R and Warrior are very effective in reducing populations even when populations are abundant.  Lannate and Thiodan are moderately effective under these conditions and Provado and Neemix are not effective.

                                                                            Mean No. of bugs / 3 plant                

Numbers in a column followed by the same letter are not significantly different, LSD, P = 0.10.