Archives for July 2021

Vegetable IPM Update 07/21/21

Sweet Corn

European corn borer (ECB) moth catches continue to be extremely low around the state.   We are in between adult generations at this time.  ECB population maps will resume if second flight catches rise to high enough numbers.

The highest nightly trap catches of ECB for the week ending 07/21/21 are as follows:

Centerton   1
Milford   1

[Read more…]

Fruit IPM for 7/21/21

Apple:

San Jose Scale (SJS): Some damage is being seen in northern county orchards where nymphs are active. Now is the time to the nymphal stage if you have problem populations. High volume applications are required for control since all twigs and surface areas where nymphs are active need to be covered. Esteem, Centaur, Venerate and Diazinon are choices for control. [Read more…]

SLF Adults Are Here (again)

Right on time with last year’s observations, adult spotted lanternflies (SLF) were found in Pilesgrove (Salem County) NJ. In 2020 adults at the same location were found on July 23 so despite the earlier hatch observed in May, the phenology is right on track.

Adults were not the dominant life stage, mostly fourth instars were observed. Now is a critical time for management efforts as even these young adults will not become reproductive until September. Adults will congregate on trees, feeding in groups to access the phloem. At this time of year they prefer black walnut and tree of heaven and will gradually move towards red maples, willow, river birch, and sycamore. There are other hosts, these are just the ones we have consistently found high numbers of adults on in NJ.

 

In 2020, adults dispersed in large numbers to commercial vineyards around September 4. I think this dispersal is a combination of depletion of resources (they are literally sucking the sap out of trees) and density. As NJ populations of SLF increase, they are depleting food resources faster. I expect this movement from wooded areas to vineyards will happen earlier this year, likely mid August. There will be a few bugs here and there, but commercial vineyard managers should wait to apply insecticides until you see the larger influx. Across sites, the 10 adults/vine threshold was reached around the same time last year – although some vineyards had much larger numbers per vine – so this is a good threshold to use for now. I will post management recommendations for the adults soon!

Vegetable Disease Update – 7/19/21

  • Phytophthora blight has been reported in pepper and cucurbit crops. For more information on Phytophthora blight control please click here.
  • Pepper anthracnose has been reported in southern New Jersey. For more information on preparing for pepper anthracnose please click here.
  • Cucurbit downy mildew has been reported on cucumber (6/16/21) and cantaloupe (6/22/21) in southern New Jersey. There have been no reports of CDM on other cucurbit hosts in the region to date. For more information on CDM and its control please click here. To track the progress of CDM please visit the CDM forecasting website.
  • No reports of Late blight in the region. To track the progress of Late blight in the US please click here.
  • Cucurbit powdery mildew has been reported on summer squash, butternut, and spaghetti squash as we are now headed into mid-summer. Please scout fields on a regular basis and initiate a preventative fungicide program if you haven’t already done so. For more information on CPM control please click here.
  • Bacterial leaf spot (BLS) continues to be reported on bell and non-bell peppers in southern New Jersey. For more information on our continuing survey for BLS and copper resistance detection in tomato and pepper please click here.
  • For an update on Dickeya dianthicola research in potato please click here.
  • The 2020/2021 Commercial Vegetable Production Recommendations Guide is available for free online.
  • For a quick review on managing fungicide resistance development using tank mixes and fungicide rotations, and information on FRAC group 4, FRAC group 7, and FRAC group 3 and FRAC group 11 fungicides please click on hyperlinks.

Monitoring for the Cranberry Toad Bug

As we approach the end of July, growers need to start monitoring for the cranberry toad bug, Phylloscelis rubra (Figure 1). In a recent study,

Cranberry toad bug

Figure 1. Cranberry toad bug.

we showed that even relatively low densities of this insect can cause significant injury to cranberries (Rodriguez-Saona et al. 2020. Characterizing the Feeding Injury Caused by Phylloscelis rubra (Hemiptera: Dictyopharidae) to Cranberries, Journal of Insect Science, 20 (6), 37, https://doi.org/10.1093/jisesa/ieaa143). Thus, monitoring for this insect from the end of July through mid-August is critical.

Life cycle. Cranberry toad bugs feed only on cranberries. This insect has a single generation per year. It overwinters as eggs. The nymphs appear by the end of June through early September, and the adults from end of July through October (harvest) (Figure 2). Eggs are laid from end of August through October.

Damage. Feeding damage can be noticed in two stages. 1st-stage feeding damage on vines causes closing in (towards the branch) of the leaves on the new growth. 2nd-stage feeding causes changed in color (reddish to brown) of new growth. The damage can be seen from July until harvest. This damage will cause dying of the branch and the berries to shrivel up (Figure 3). Heavy infestation will result in dwarfed

Seasonal changes of the cranberry toad bug.

Figure 2. Seasonal changes of the cranberry toad bug.

berries.

Management. To determine infestation, lightly sweep problematic beds (bugs should be easy to catch in sweep nets as they are very active). Currently there is no threshold established for this pest. Thus, insecticide applications should be based on the relative number of bugs per sweep compared with other sites and previous history of infestation. If needed, growers can use the following control options: Sevin 4F (broad-spectrum carbamate), Diazinon, Imidan 70W (broad-spectrum organophosphates), Actara or Assail 30SG (neonicotinoid insecticides, effective against piercing-sucking insects). If infestation is high, treatments should be applied in early August for best control.

Injury caused by the cranberry toad bug.

Figure 3. Injury caused by the cranberry toad bug.

Field crop progress mid-July, Salem County

Crop fields continue to be a smorgesborg for insect and insect vectored pathogens. With four different planting groups of soybean and three of corn, foliar and silk clipping pests are making their presence known in soybeans and corn.

Corn: Japanese beetle feeding continues to expand across soybean fields. The abundance of healthy stands and silk emergence in early planted corn will shift these leaf feeders over to corn silks. This planting group is overall in excellent condition and most fields have obtained maxiumum height and nitrogen utilization. These fields have very high stand populations and leaf development. Hopefully this will help mitigate the edge feeding losses from Japanese beetles and another silk clipper, stinkbugs. In the coming weeks after pollination, good air flow and lower humidity through grain fill is needed to limit mycotoxin development.

Late May and June planted corn up to three feet in height oversaturated just prior to planting continues to show signs of moisture stress, and soil compaction issues. These fields are in the rapid stem elongation phase and were leaf curling this week in the high heat. Several fields are symptomatic for nitrogen deficiency as a result of those earlier ponding events. Soils are sunbaked on the surface and fields with higher clay content are root zone compacted. These are the fields to monitor for economic damage from silk clipping if the crop continues to be under heat stress. To limit further yield losses, these acres are more likely to benefit from insecticide treatments during silking still a few weeks away. Stink bugs in V1 to V6 plantings are most likely to be of economic concern and treatable in this corn group when 1 out of ten plants have bugs; decreasing to 1 out of every four at reproductive stage.

July planted corn is less effected by moisture and heat stress. The root systems of these v1 to v5 plantings have found adequate surface soil moisture from last week’s rains and are loving this heat and humidity. This crop group is highly variable for soil compaction depending on the quality of the soil and the path of heavy rainfall just prior to planting.

Soybeans: Overwintering pests of concern vectoring diseases to soybeans have emerged in abudance from vegetation in field edges, old meadows, and grass hay fields. The acreage and variability in cover crop plantings and cash grain crop plantings last fall was ideal for insect populations and residue infected bacterial innoculums to increase.

Along the south-west side of the county, in uncanopied vegetative beans on sandy soils, wind-rain-sand deposition of soil onto leaves occurred in recent storms and disease progression is evident on stems and leaves. Field comparisions here observed tillage at planting reduced movement of bacterial innoculum onto stems and leaves in canopied stands in contrast to adjacent no-tilled early vegetative stands. On the opposite corner of the county, oversaturated, low-lying loamy fields recently fitted for planting are showing expected variablity in stand establishment.

Adult soybean stem borer

Soybean stem borer adults are present in bean after bean fields

On better ground without compaction issues, most early planted fields are in good foliage condition.  Early R stage beans that were under heat and moisture stress last week show signs of self-abortion of lower stem flowers. Management of insect feeding and variatal resistance response in these fields is optimum. Crop rotation matched to soil type and timing of inputs stands out as the key niche for uniform early planted stand evaluations. In these ideal stands, evaluate what combination of variety, tillage, prior crop rotation, planting date, and timing of inputs and preciptation thwarted insect vectored diseases.

Observations on later planted beans are quite variable regardless of when inputs were applied. Grasshoppers, japanese beetles, spider mites and thrips have already vectored leaf diseases in this group. Soybean stem borer adults and larva were observed in v4 to v5 fields.

Knowing the weather was just not ideal for this planting group, document signs and progression of insect vectored diseases in the foliage, exterior of stems, interior of stems, cross section of roots, feeder root presence and presence of healthy nitrogen fixing bacteria by variety.

Healthy stems and roots in the vegetative stage are a good sign plants will respond to foliar feeds if needed. Expect insect pressure to continue to build. Soybean diseases overlap as do insect stages and feeding pressure. While one pathogen may be of minimal concern in early planted beans, another may take over second plantings and dominate later plantings as season progresses.