PHI for HopGuard: Harvest Timing After Hop Beta Acid Treatment

HopGuard is one of only two treatments labeled for use with honey supers in place at any time. That's a short list, and it's why HopGuard has a dedicated following among beekeepers who manage production colonies with active supers and need a varroa treatment option that doesn't force a harvest disruption.

The PHI for HopGuard honey harvest is 0 days. You can apply HopGuard with supers on and harvest from those supers the same day the treatment is complete. There's no waiting period, no super removal requirement, and no PHI restriction on your harvest.

TL;DR

PHI (pre-harvest interval) is the required waiting period between the end of treatment and adding honey supers
PHI varies by product: oxalic acid has no PHI for approved uses, MAQS has no PHI, Apivar requires supers to be off during treatment
Applying treatments with supers on violates the label and may contaminate honey with residues
State apiarists can ask for PHI compliance records during inspections
Missing PHI windows is one of the most common compliance errors among small-scale beekeepers
VarroaVault's PHI calendar blocks super-addition dates automatically based on your logged treatment dates

What Makes HopGuard Different

Most varroa treatments fall into one of two categories: treatments that require super removal (Apivar, Apistan, coumaphos) or treatments that have 0-day PHI but with nuanced during-treatment restrictions (MAQS, OA products). HopGuard is in a third category: genuinely unrestricted use with supers present at any time.

This is because HopGuard's active ingredient, hops beta acids (beta acids from Humulus lupulus, the hop plant), is a naturally occurring compound from an agricultural crop. The EPA determined that its application to colonies does not produce concerning residues in honey at labeled doses, resulting in the clean-label PHI status.

HopGuard is one of only two treatments labeled for use with honey supers in place at any time. (MAQS is the other, with the during-treatment nuances described in its own guide.)

HopGuard Protocol

HopGuard comes as strips impregnated with hop beta acids. The strips are placed on or between frames in the brood nest area.

Standard application: 1 strip per 5 frames of bees (some product versions) or as specified on your current product label. Placement in the brood nest area where bee contact is highest.

Treatment period: Varies by product version, typically 30 days or until the strip is depleted. Check your label.

Conditions: No temperature restrictions analogous to formic acid or thymol. HopGuard works across a wider temperature range, which is an advantage in both early spring and late fall.

Supers: Can remain in place throughout treatment. No restrictions.

Can I Harvest Honey Immediately After HopGuard Treatment?

Yes. The 0-day PHI with no during-treatment super restriction means honey in supers present throughout the entire HopGuard treatment period can be harvested immediately after treatment ends, or even before treatment ends, since supers can remain on and honey can accumulate normally.

HopGuard treatment log automatically confirms the 0-day PHI and marks harvest as immediately permitted in VarroaVault.

This is the simplest PHI compliance scenario in the varroa treatment toolkit. There's no countdown, no removal-date tracking for PHI purposes, and no conflict with harvest timing.

Is HopGuard as Effective as Other Treatments?

This is a fair question, and the honest answer is: efficacy results are more variable than with first-line treatments like Apivar or formic acid products.

Published studies on HopGuard show mite reduction in the range of 40-70% in colonies with brood present. That's meaningful reduction but lower than the 90%+ achievable with correctly applied Apivar or formic acid.

The efficacy gap has implications for how HopGuard fits in a varroa management program:

Best use cases:

Maintenance treatment between heavier interventions, knocking down mite loads that are starting to build
Colonies with moderate mite loads where you want to treat without disrupting production
Stop-gap treatment when temperature conditions preclude formic acid and synthetic treatment would require a production-disruptive super removal

Less appropriate when:

Mite loads are high (above 4-5%) and require aggressive knockdown
You're approaching the fall treatment window where maximum efficacy is paramount
You've already seen two consecutive HopGuard treatments with poor results

Combining HopGuard With Your Varroa Program

Many beekeepers use HopGuard as one component of a broader program rather than as a standalone primary treatment. Examples:

Production-season maintenance: Apply HopGuard during peak honey flow to suppress mite build-up, then follow with a more aggressive treatment (Apivar, OA extended protocol) after supers come off in fall.

Between major treatments: After fall Apivar completes, a winter OA dribble is the preferred follow-up. If counts start climbing again in spring before full-scale treatment is warranted, a HopGuard application during the spring build-up can slow the trajectory.

First-year beekeepers: The simple application protocol and clean PHI status make HopGuard accessible for new beekeepers who are still building confidence with varroa management. Starting with HopGuard while learning other methods is a reasonable approach, understanding that post-treatment counts are always necessary to verify efficacy.

How Do I Log HopGuard in VarroaVault?

In the colony treatment log, select HopGuard from the treatment menu. Enter:

Application date
Number of strips applied
Estimated strip depletion date (or end-of-treatment date per your label)
Pre-treatment mite count (baseline, always log this)

VarroaVault automatically marks the PHI as 0 days and confirms no super restriction applies. After logging, a post-treatment count reminder fires at the appropriate interval so you can verify efficacy.

The system doesn't generate PHI warnings for HopGuard harvest events, because there are none. The compliance picture is simple: treat, harvest whenever you want.

For tracking your HopGuard history and efficacy over time, the hopguard tracking feature in VarroaVault keeps your full application records alongside your count history. For comparing HopGuard PHI to other treatments you're managing across your apiary, the pre-harvest interval tracker shows all active treatments and their status.

Can I harvest honey immediately after HopGuard treatment?

Yes. HopGuard has a 0-day PHI with no during-treatment or post-treatment restrictions on honey supers. Supers can be present throughout the entire treatment period and honey from those supers can be harvested at any point, during treatment or after. There is no waiting period, no super removal requirement, and no PHI countdown to track.

Is HopGuard as effective as other treatments?

HopGuard achieves 40-70% mite reduction in studies of colonies with brood present. This is lower than first-line treatments like Apivar (90%+) or formic acid products (80-95% under correct conditions). HopGuard is most appropriate for maintenance treatment between major interventions, moderate mite loads during production season, or situations where synthetic or formic acid treatments aren't feasible. For high mite loads or fall treatment where maximum knockdown is critical, HopGuard is generally not sufficient as a standalone treatment.

How do I log HopGuard in VarroaVault?

Open the colony treatment log, select HopGuard, and enter the application date, strips applied, and treatment end date. VarroaVault automatically applies the 0-day PHI with no super restrictions and confirms harvest as immediately permitted. A post-treatment count reminder is scheduled at the appropriate interval. No PHI conflict checking is performed for HopGuard harvest events, because no PHI applies.

How do I know if my varroa treatment is working?

Run a mite count 2-4 weeks after the treatment ends and compare it to your pre-treatment count. The efficacy formula is: ((pre-count - post-count) / pre-count) x 100. A result above 90% indicates effective treatment. Results below 80% should trigger investigation for possible resistance, application error, or reinfestation. Log both counts in VarroaVault to track efficacy trends across treatment cycles.

How often should I check mite levels in my hives?

At minimum, once per month (every 3-4 weeks) during the active season. Increase to every 2 weeks when counts are near threshold or after a treatment to verify it worked. In fall, monitoring frequency matters most because the window to treat before winter bees are raised is narrow. VarroaVault's monitoring reminders can be set to your preferred interval for each apiary.

What records should I keep for varroa management?

Each record should include: date of count or treatment, hive identifier, monitoring method used, number of bees sampled, mites counted, infestation percentage, treatment product name and EPA registration number, dose applied, treatment start and end dates, and PHI end date. State apiarists typically expect this level of detail during inspections. VarroaVault captures all of these fields in a single log entry.

Sources

American Beekeeping Federation (ABF)
USDA ARS Bee Research Laboratory
Honey Bee Health Coalition
Penn State Extension Apiculture Program
Project Apis m.

Get Started with VarroaVault

PHI compliance is not complicated when your treatment dates and harvest windows are tracked in the same system. VarroaVault automatically calculates PHI end dates for every treatment you log and blocks honey super addition during restricted periods. Start your free trial at varroavault.com.