COLLATERAL ASSIGNMENT, PATENT MORTGAGE
                             AND SECURITY AGREEMENT

     This Collateral Assignment, Patent Mortgage and Security Agreement is made
as of the 28th day of April, 1997, by and between EcoScience Corporation
("Assignor"), and Silicon Valley Bank, a California banking corporation
("Assignee").

                                    RECITALS

     A. Assignee has agreed to lend to Assignor certain funds (the "Loans"),
pursuant to a Loan and Security Agreement dated substantially even date herewith
(the "Loan Agreement") and Assignor desires to borrow such funds from Assignee.

     B. In order to induce Assignee to make the Loans, Assignor has agreed to
assign certain intangible property to Assignee for purposes of securing the
obligations of Assignor to Assignee.

              NOW, THEREFORE, THE PARTIES HERETO AGREE AS FOLLOWS:

     1. Assignment, Patent Mortgage and Grant of Security Interest. As
collateral security for the prompt and complete payment and performance of all
of Assignor's present or future indebtedness, obligations and liabilities to
Assignee, Assignor hereby assigns, transfers, conveys and grants a security
interest and mortgage to Assignee, as security, but not as an ownership
interest, in and to Assignor's entire right, title and interest in, to and under
the following (all of which shall collectively be called the "Collateral"):

          (a) All of present and future United States registered copyrights and
copyright registrations, including, without limitation, the registered
copyrights listed in Exhibit A-1 to this Agreement (and including all of the
exclusive rights afforded a copyright registrant in the United States under 17
U.S.C. ss.106 and any exclusive rights which may in the future arise by act of
Congress or otherwise) and all present and future applications for copyright
registrations (including applications for copyright registrations of derivative
works and compilations) (collectively, the "Registered Copyrights"), and any and
all royalties, payments, and other amounts payable to Assignor in connection
with the Registered Copyrights, together with all renewals and extensions of the
Registered Copyrights, the right to recover for all past, present, and future
infringements of the Registered Copyrights, and all computer programs, computer
databases, computer program flow diagrams, source codes, object codes and all
tangible property embodying or incorporating the Registered Copyrights, and all
other rights of every kind whatsoever accruing thereunder or pertaining thereto.

          (b) All present and future copyrights which are not registered in the
United States Copyright Office (the "Unregistered Copyrights"), whether now
owned or hereafter acquired, including without limitation the Unregistered
Copyrights listed in Exhibit A-2 to this Agreement, and any and all royalties,
payments, and other amounts payable to Assignor in connection with the
Unregistered Copyrights, together with all renewals and extensions of the
Unregistered Copyrights, the right to recover for all past, present, and future
infringements of the Unregistered Copyrights, and all computer programs,
computer databases, computer program flow diagrams, source codes, object codes
and all tangible property embodying or incorporating the Unregistered
Copyrights, and all other rights of every kind whatsoever accruing thereunder or
pertaining thereto. The Registered Copyrights and the Unregistered Copyrights
collectively are referred to herein as the "Copyrights."

          (c) All right, title and interest in and to any and all present and
future license agreements with respect to the Copyrights, including without
limitation the license agreements listed in Exhibit A-3 to this Agreement (the
"Licenses").

          (d) All present and future accounts, accounts receivable and other
rights to payment arising from, in connection with or relating to the
Copyrights.

          (e) Any and all trade secrets, and any and all intellectual property
rights in computer software and computer software products now or hereafter
existing, created, acquired or held;
<PAGE>

          (f) Any and all design rights which may be available to Assignor now
or hereafter existing, created, acquired or held;

          (g) All patents, patent applications and like protections including,
without limitation, improvements, divisions, continuations, renewals, reissues,
extensions and continuations-in-part of the same, including without limitation
the patents and patent applications set forth on Exhibit B attached hereto
(collectively, the "Patents");

          (h) Any trademark and servicemark rights, whether registered or not,
applications to register and registrations of the same and like protections, and
the entire goodwill of the business of Assignor connected with and symbolized by
such trademarks, including without limitation those set forth on Exhibit C
attached hereto (collectively, the "Trademarks")

          (i) Any and all claims for damages by way of past, present and future
infringements of any of the rights included above, with the right, but not the
obligation, to sue for and collect such damages for said use or infringement of
the intellectual property rights identified above;

          (j) All licenses or other rights to use any of the Copyrights, Patents
or Trademarks, and all license fees and royalties arising from such use to the
extent permitted by such license or rights;

          (k) All amendments, extensions, renewals and extensions of any of the
Copyrights, Trademarks or Patents; and

          (l) All proceeds and products of the foregoing, including without
limitation all payments under insurance or any indemnity or warranty payable in
respect of any of the foregoing.

THE INTEREST IN THE COLLATERAL BEING ASSIGNED HEREUNDER SHALL NOT BE CONSTRUED
AS A CURRENT ASSIGNMENT, BUT AS A CONTINGENT ASSIGNMENT TO SECURE ASSIGNOR'S
OBLIGATIONS TO ASSIGNEE UNDER THE LOAN AGREEMENT.

     2. Authorization and Request. Assignor authorizes and requests that the
Register of Copyrights and the Commissioner of Patents and Trademarks record
this conditional assignment.

     3. Covenants and Warranties. Assignor represents, warrants, covenants and
agrees as follows:

          (a) Assignor is now the sole owner of the Collateral, except for
non-exclusive licenses granted by Assignor to its customers in the ordinary
course of business*.

*and one exclusive license granted by Assignor to Terminix International
Company, L.P. for the sale and marketing of Bio-Blast.

          (b) Listed on Exhibits A-1 and A-2 are all copyrights owned by
Assignor, in which Assignor has an interest, or which are used in Assignor's
business.

          (c) Each employee, agent and/or independent contractor who has
participated in the creation of the property constituting the Collateral has
either executed an assignment of his or her rights of authorship to Assignor or
is an employee of Assignor acting within the scope of his or her employment and
was such an employee at the time of said creation.

          (d) All of Assignor's present and future software, computer programs
and other works of authorship subject to United States copyright protection, the
sale, licensing or other disposition of which results in royalties receivable,
license fees receivable, accounts receivable or other sums owing to Assignor
(collectively, "Receivables"), have been and shall be registered with the United
States Copyright Office prior to the date Assignor requests or accepts any loan
from Assignee with respect to such Receivables and prior to the date Assignor
includes 

                                      -2-
<PAGE>

any such Receivables in any accounts receivable aging, borrowing base
report or certificate or other similar report provided to Assignee, and Assignor
shall provide to Assignee copies of all such registrations promptly upon the
receipt of the same.

          (e) Assignor shall undertake all reasonable measures to cause its
employees, agents and independent contractors to assign to Assignor all rights
of authorship to any copyrighted material in which Assignor has or may
subsequently acquire any right or interest.

          (f) Performance of this Assignment does not conflict with or result in
a breach of any agreement to which Assignor is bound, except to the extent that
certain intellectual property agreements prohibit the assignment of the rights
thereunder to a third party without the licensor's or other party's consent and
this Assignment constitutes an assignment.

          (g) During the term of this Agreement, Assignor will not transfer or
otherwise encumber any interest in the Collateral, except for non-exclusive
licenses granted by Assignor in the ordinary course of business or as set forth
in this Assignment;

          (h) Each of the Patents is valid and enforceable, and no part of the
Collateral has been judged invalid or unenforceable, in whole or in part, and no
claim has been made that any part of the Collateral violates the rights of any
third party;

          (i) Assignor shall promptly advise Assignee of any material adverse
change in the composition of the Collateral, including but not limited to any
subsequent ownership right of the Assignor in or to any Trademark, Patent or
Copyright not specified in this Assignment;

          (j) Assignor shall (i) protect, defend and maintain the validity and
enforceability of the Trademarks, Patents and Copyrights, (ii) use its best
efforts to detect infringements of the Trademarks, Patents and Copyrights and
promptly advise Assignee in writing of material infringements detected and (iii)
not allow any Trademarks, Patents, or Copyrights to be abandoned, forfeited or
dedicated to the public without the written consent of Assignee, which shall not
be unreasonably withheld unless Assignor determines that reasonable business
practices suggest that abandonment is appropriate.

          (k) Assignor shall promptly register the most recent version of any of
Assignor's Copyrights, if not so already registered, and shall, from time to
time, execute and file such other instruments, and take such further actions as
Assignee may reasonably request from time to time to perfect or continue the
perfection of Assignee's interest in the Collateral;

          (l) This Assignment creates, and in the case of after acquired
Collateral, this Assignment will create at the time Assignor first has rights in
such after acquired Collateral, in favor of Assignee a valid and perfected first
priority security interest in the Collateral in the United States securing the
payment and performance of the obligations evidenced by the Loan Agreement upon
making the filings referred to in clause (m) below;

          (m) To its knowledge, except for, and upon, the filing with the United
States Patent and Trademark office with respect to the Patents and Trademarks
and the Register of Copyrights with respect to the Copyrights necessary to
perfect the security interests and assignment created hereunder and except as
has been already made or obtained, no authorization, approval or other action
by, and no notice to or filing with, any U.S. governmental authority or U.S.
regulatory body is required either (i) for the grant by Assignor of the security
interest granted hereby or for the execution, delivery or performance of this
Assignment by Assignor in the U.S. or (ii) for the perfection in the United
States or the exercise by Assignee of its rights and remedies thereunder;

          (n) All information heretofore, herein or hereafter supplied to
Assignee by or on behalf of Assignor with respect to the Collateral is accurate
and complete in all material respects.

          (o) Assignor shall not enter into any agreement that would materially
impair or conflict with Assignor's obligations hereunder without Assignee's
prior written consent, which consent shall not be unreasonably

                                      -3-
<PAGE>

withheld. Assignor shall not permit the inclusion in any material contract to
which it becomes a party of any provisions that could or might in any way
prevent the creation of a security interest in Assignor's rights and interest in
any property included within the definition of the Collateral acquired under
such contracts, except that certain contracts may contain anti-assignment
provisions that could in effect prohibit the creation of a security interest in
such contracts.

          (p) Upon any executive officer of Assignor obtaining actual knowledge
thereof, Assignor will promptly notify Assignee in writing of any event that
materially adversely affects the value of any material Collateral, the ability
of Assignor to dispose of any material Collateral or the rights and remedies of
Assignee in relation thereto, including the levy of any legal process against
any of the Collateral.

     4. Assignee's Rights. Assignee shall have the right, but not the
obligation, to take, at Assignor's sole expense, any actions that Assignor is
required under this Assignment to take but which Assignor fails to take, after
fifteen (15) days' notice to Assignor. Assignor shall reimburse and indemnify
Assignee for all reasonable costs and reasonable expenses incurred in the
reasonable exercise of its rights under this section 4.

     5. Inspection Rights. Assignor hereby grants to Assignee and its employees,
representatives and agents the right to visit, during reasonable hours upon
prior reasonable written notice to Assignor, and any of Assignor's plants and
facilities that manufacture, install or store products (or that have done so
during the prior six-month period) that are sold utilizing any of the
Collateral, and to inspect the products and quality control records relating
thereto upon reasonable written notice to Assignor and as often as may be
reasonably requested, but not more than one (1) in every six (6) months;
provided, however, nothing herein shall entitle Assignee access to Assignor's
trade secrets and other proprietary information.

     6. Further Assurances; Attorney in Fact.

          (a) Upon an Event of Default, on a continuing basis thereafter,
Assignor will, subject to any prior licenses, encumbrances and restrictions and
prospective licenses, make, execute, acknowledge and deliver, and file and
record in the proper filing and recording places in the United States, all such
instruments, including, appropriate financing and continuation statements and
collateral agreements and filings with the United States Patent and Trademarks
Office and the Register of Copyrights, and take all such action as may
reasonably be deemed necessary or advisable, or as requested by Assignee, to
perfect Assignee's security interest in all Copyrights, Patents and Trademarks
and otherwise to carry out the intent and purposes of this Collateral
Assignment, or for assuring and confirming to Assignee the grant or perfection
of a security interest in all Collateral.

          (b) Upon an Event of Default, Assignor hereby irrevocably appoints
Assignee as Assignor's attorney-in-fact, with full authority in the place and
stead of Assignor and in the name of Assignor, Assignee or otherwise, from time
to time in Assignee's discretion, upon Assignor's failure or inability to do so,
to take any action and to execute any instrument which Assignee may deem
necessary or advisable to accomplish the purposes of this Collateral Assignment,
including:

               (i) To modify, in its sole discretion, this Collateral Assignment
without first obtaining Assignor's approval of or signature to such modification
by amending Exhibit A-1, Exhibit A-2, Exhibit A-3, Exhibit B and Exhibit C,
thereof, as appropriate, to include reference to any right, title or interest in
any Copyrights, Patents or Trademarks acquired by Assignor after the execution
hereof or to delete any reference to any right, title or interest in any
Copyrights, Patents or Trademarks in which Assignor no longer has or claims any
right, title or interest; and

               (ii) To file, in its sole discretion, one or more financing or
continuation statements and amendments thereto, relative to any of the
Collateral without the signature of Assignor where permitted by law.

     7. Events of Default. The occurrence of any of the following shall
constitute an Event of Default under the Assignment:

                                      -4-
<PAGE>

          (a) An Event of Default occurs under the Loan Agreement; or

          (b) Assignor breaches any warranty or agreement made by Assignor in
this Assignment.

     8. Remedies. Upon the occurrence and continuance of an Event of Default,
Assignee shall have the right to exercise all the remedies of a secured party
under the California Uniform Commercial Code, including without limitation the
right to require Assignor to assemble the Collateral and any tangible property
in which Assignee has a security interest and to make it available to Assignee
at a place designated by Assignee. Assignee shall have a nonexclusive, royalty
free license to use the Copyrights, Patents and Trademarks to the extent
reasonably necessary to permit Assignee to exercise its rights and remedies upon
the occurrence of an Event of Default. Assignor will pay any expenses (including
reasonable attorney's fees) incurred by Assignee in connection with the exercise
of any of Assignee's rights hereunder, including without limitation any expense
incurred in disposing of the Collateral. All of Assignee's rights and remedies
with respect to the Collateral shall be cumulative.

     9. Indemnity. Assignor agrees to defend, indemnify and hold harmless
Assignee and its officers, employees, and agents against: (a) all obligations,
demands, claims, and liabilities claimed or asserted by any other party in
connection with the transactions contemplated by this Agreement, and (b) all
losses or expenses in any way suffered, incurred, or paid by Assignee as a
result of or in any way arising out of, following or consequential to
transactions between Assignee and Assignor, whether under this Assignment or
otherwise (including without limitation, reasonable attorneys fees and
reasonable expenses), except for losses arising form or out of Assignee's gross
negligence or willful misconduct.

     10. Release. At such time as Assignor shall completely satisfy all of the
obligations secured hereunder, Assignee shall execute and deliver to Assignor
all assignments and other instruments as may be reasonably necessary or proper
to terminate Assignee's security interest in the Collateral, subject to any
disposition of the Collateral which may have been made by Assignee pursuant to
this Agreement. For the purpose of this Agreement, the obligations secured
hereunder shall be deemed to continue if Assignor enters into any bankruptcy or
similar proceeding at a time when any amount paid to Assignee could be ordered
to be repaid as a preference or pursuant to a similar theory, and shall continue
until it is finally determined that no such repayment can be ordered.

     11. No Waiver. No course of dealing between Assignor and Assignee, nor any
failure to exercise nor any delay in exercising, on the part of Assignee, any
right, power, or privilege under this Agreement or under the Loan Agreement or
any other agreement, shall operate as a waiver. No single or partial exercise of
any right, power, or privilege under this Agreement or under the Loan Agreement
or any other agreement by Assignee shall preclude any other or further exercise
of such right, power, or privilege or the exercise of any other right, power, or
privilege by Assignee.

     12. Rights Are Cumulative. All of Assignee's rights and remedies with
respect to the Collateral whether established by this Agreement, the Loan
Agreement, or any other documents or agreements, or by law shall be cumulative
and may be exercised concurrently or in any order.

     13. Course of Dealing. No course of dealing, nor any failure to exercise,
nor any delay in exercising any right, power or privilege hereunder shall
operate as a waiver thereof.

     14. Attorneys' Fees. If any action relating to this Assignment is brought
by either party hereto against the other party, the prevailing party shall be
entitled to recover reasonable attorneys fees, costs and disbursements.

     15. Amendments. This Assignment may be amended only by a written instrument
signed by both parties hereto. To the extent that any provision of this
Agreement conflicts with any provision of the Loan Agreement, the provision
giving Assignee greater rights or remedies shall govern, it being understood
that the purpose of this Agreement is to add to, and not detract from, the
rights granted to Assignee under the Loan Agreement. This Agreement, the Loan
Agreement, and the documents relating thereto comprise the entire agreement of
the parties with respect to the matters addressed in this Agreement.

                                      -5-
<PAGE>

     16. Severability. The provisions of this Agreement are severable. If any
provision of this Agreement is held invalid or unenforceable in whole or in part
in any jurisdiction, then such invalidity or unenforceability shall affect only
such provision, or part thereof, in such jurisdiction, and shall not in any
manner affect such provision or part thereof in any other jurisdiction, or any
other provision of this Agreement in any jurisdiction.

     17. Counterparts. This Assignment may be executed in two or more
counterparts, each of which shall be deemed an original but all of which
together shall constitute the same instrument.

     18. California Law and Jurisdiction. This Assignment shall be governed by
the laws of the State of California, without regard for choice of law
provisions. Assignor and Assignee consent to the nonexclusive jurisdiction of
any state or federal court located in Santa Clara County, California.

     19. Confidentiality. In handling any confidential information, Assignee
shall exercise the same degree of care that it exercises with respect to its own
proprietary information of the same types to maintain the confidentiality of any
non-public information thereby received or received pursuant to this Assignment
except that the disclosure of this information may be made (i) to the affiliates
of the Assignee, (ii) to prospective transferee or purchasers of an interest in
the obligations secured hereby, provided that they have entered into a
comparable confidentiality agreement in favor of Assignor and have delivered a
copy to Assignor, (iii) as required by law, regulation, rule or order, subpoena
judicial order or similar order and (iv) as may be required in connection with
the examination, audit or similar investigation of Assignee.

     20. WAIVER OF RIGHT TO JURY TRIAL. ASSIGNEE AND ASSIGNOR EACH HEREBY WAIVE
THE RIGHT TO TRIAL BY JURY IN ANY ACTION OR PROCEEDING BASED UPON, ARISING OUT
OF, OR IN ANY WAY RELATING TO: (I) THIS AGREEMENT; OR (II) ANY OTHER PRESENT OR
FUTURE INSTRUMENT OR AGREEMENT BETWEEN ASSIGNEE AND ASSIGNOR; OR (III) ANY
CONDUCT, ACTS OR OMISSIONS OF ASSIGNEE OR ASSIGNOR OR ANY OF THEIR DIRECTORS,
OFFICERS, EMPLOYEES, AGENTS, ATTORNEYS OR ANY OTHER PERSONS AFFILIATED WITH
ASSIGNEE OR ASSIGNOR; IN EACH OF THE FOREGOING CASES, WHETHER SOUNDING IN
CONTRACT OR TORT OR OTHERWISE.

     IN WITNESS WHEREOF, the parties hereto have executed this Assignment on the
day and year first above written.

Address of Assignor:                             ASSIGNOR:

10 Alvin Court
East Brunswick, NJ  08816                        ECOSCIENCE CORPORATION


                                                 By:    /s/ Harold A. Joannidi
                                                 Name:  Harold A. Joannidi

                                      -6-
<PAGE>

STATE OF NEW JERSEY                 )
                                        ) ss.
COUNTY OF MIDDLESEX                 )

     On May 2, 1997, before me, Marianne Colucci, Notary Public, personally
appeared Harold Joannidi, personally known to me (or proved to me on the basis
of satisfactory evidence) to be the person(s) whose name(s) is/are subscribed to
the within instrument and acknowledged to me that he/she/they executed the same
in his/her/their authorized capacity(ies), and that by his/her/their
signature(s) on the instrument the person(s), or the entity upon behalf of which
the person(s) acted, executed the instrument.

     Witness my hand and official seal.


                              /s/ Marianne Colucci

                                     (Seal)

                                      -7-
<PAGE>

Exhibit "A-1" attached to that certain Collateral Assignment, Patent Mortgage
and Security Agreement

                                  EXHIBIT "A-1"

                              REGISTERED COPYRIGHTS

REG. NO.                       REG. DATE                       COPYRIGHT
--------                       ---------                       ---------

                                      NONE

                                      -8-
<PAGE>

Exhibit "A-2" attached to that certain Collateral Assignment, Patent Mortgage
and Security Agreement

                                  EXHIBIT "A-2"

                             UNREGISTERED COPYRIGHTS

                            DESCRIPTION OF COPYRIGHTS

                                      NONE

                                      -9-
<PAGE>

Exhibit "A-3" attached to that certain Collateral Assignment, Patent Mortgage
and Security Agreement

                                  EXHIBIT "A-3"

                        DESCRIPTION OF LICENSE AGREEMENTS

                                      NONE

                                      -10-
<PAGE>

Exhibit "B" attached to that certain Collateral Assignment, Patent Mortgage and
Security Agreement

                                   EXHIBIT "B"

                                     PATENTS

TITLE                                  SERIAL NO.            FILING DATE
-----                                  ----------            -----------

Insect Contamination Chamber            D324406              March 3, 1992

Method and Device for the
Biological Control of Cockroaches       5057315              October 15, 1991

Method and Device for the
Biological Control of Insects           5057316              October 15, 1991

Method and Device for the
Biological Control of Flying Insects    5189831              March 2, 1993


Device for the Biological
Control of Cockroaches                  5310552              May 10, 1994


Device Containing Fungus for
the Biological Control of Insects       5427784              June 27, 1995


Maintenance and Long Term
Stabilization of Fungal Conidia
Using Surfactants                       5512280              April 30, 1996

Pseudomonas Syringae Atcc
55389 and Use Thereof for
Inhibiting Microbial Decay on Fruit     5554368              September 10, 1996

                                      -11-
<PAGE>

Exhibit "C" attached to that certain Collateral Assignment, Patent Mortgage and
Security Agreement

                                   EXHIBIT "C"

                                   TRADEMARKS

MARK                        REG./FILE DATE    APP./SERIAL NO.       STATUS
----                        --------------    ---------------       ------

EcoScience with the
    EcoScience logo

Bio-Path

Horizontal Transfer

Nature Seal (as sublicensee)

Bio-Blast

Bio-Save

Back-Off

                                      -12-